Monthly Weather Summary

Blowing Snow
March 2011. - Warm and Windy.

Wind was the notable weather element for March 2011. Gale force winds (greater than 63km/hr) were recorded on 25 days – 10 more than the long term average for March at Mawson. Winds greater than 41km/h were recorded on all days. The maximum wind gust for March was 165km/h well short of the record gust for March of 185km/h. It came on the 2nd of three days of blizzard*. The average daily wind run (the measure of how many kilometers of wind pass the station in 24 hours) and the total wind run for the month were in excess of previous high values setting new records. The average hourly wind speed was 56 km/h across the whole month. 1354 km of wind passed the station each day on average, totaling 41,968 km for the month. That is a little more than the circumference of earth at the equator.

Highest and lowest maximum and minimum temperatures didn’t go close to any records however the average maximum and minimum temperatures were both above the long term monthly average. The average maximum for the month of -6.1oC was 1oC above and the long term average. The monthly average minimum of -12.7oC was half a degree above the long term average.

* Blizzard is defined as wind in excess of 63km/h for more than an hour with visibility reduced to less than 100m by blowing snow and sub zero temperatures.
Weather statistics for March

April Sunrise.
April 2011. - Close to Average.

In general the weather for April was close to average with no records even remotely challenged.
- at Mawson during April we expect:
Temperatures

  • A maximum temperature about -11.7°C. The average maximum for the month was 11.1°C. The coldest maximum was -17.5°C and the warmest -1.7°C
  • A minimum temperature about -17.3°C. The average minimum for the month was exactly 17.3°C. The coldest minimum was -24.1°C and the warmest -4.7°C.

The coldest April day on record at Mawson was on 23rd April 1998 when the maximum temperature struggled to reach -28.3°C and the minimum fell to -33.3°C.

Wind:
  • The average daily wind run (the measure of how many kilometres of wind pass the station in 24 hours) was 1008km. This is a little above the long term average of 944km. It falls along way short of the highest average daily April wind run for Mawson recorded which was 1365km for April 2000.
  • The maximum wind gust for April was a modest 161km/h recorded on the 7th April. The record gust for April is 234km/h recorded in 1972.
  • 4 days of blizzard conditions were recorded for April which is the same as average. There were 16 gale days, 27 days of strong wind and 7 days when snowfall was observed.

Sunshine
  • During April the days at Mawson shortened by about 3hours 45min – close to 8 minutes a day. On 30th April sunrise was at 9:12am and sunset at 4:18pm and the sun rose just 7 degrees above the horizon. The average daily recorded sunshine for the month at 4.2 hours, slightly higher than the monthly average of 3.9 hours.
Weather Statistics for April.

Activities at Mawson during April that were impacted by adverse weather included a field training expedition to the Masson and David Range on 6th, 7th and 8th April that was postponed because of blizzard conditions. The crew working for 4 days outside repairing a major leak between the melt bell and storage tanks endured daytime temperatures less than -15°C in winds around 30kts. In better conditions the work could have been completed in a day. Low dew point temperatures made the apparent temperature (wind chill) much colder.

Solar Halo in Cirrostratus cloud.
May 2011. Windy.
May was close to average except for total wind run that was within 5% of the long term record indicating that the month had plenty of windy days but none extreme enough go close to the record gust of 208km/h.

Temperatures - at Mawson during May we expect:
  • A maximum temperature about -13.4°C. The average maximum for the month was -13.2°C. The coldest maximum was –22.4°C and the warmest -3.1°C
  • A minimum temperature about -19.2°C. The average minimum for the month was -19.1°C. The coldest minimum was -27.8°C and the warmest -7.2°C.

The coldest May day on record at Mawson was on 22rd May 1964 when the maximum temperature struggled to reach -30°C and the minimum fell to -34.4°C.

Wind:
  • The average daily wind run (the measure of how many kilometres of wind pass the station in 24 hours) was 1246km each day. This was above the long term average of 976km. It falls along way short of the highest average daily May wind run for Mawson recorded in May 2007 - 1538km.
  • The maximum wind gust for May was a modest 156km/h from SSE recorded on the 7th May. The record gust for May is 208km/h from SE recorded on the 10th May 1996.
  • 4 days of blizzard conditions were recorded for May which is below the average of 5. There were 19 gale days, 28 days of strong wind and 6 days when snowfall was observed.
Sunshine
  • During May the days at Mawson
Weather Statistics for May.

Activities at Mawson impacted by adverse weather.
The Korean film crew and Field Training Officer were stranded at Macey hut for 4 days from the 6th due to blizzard conditions. A number planned recreational trips were cancelled due to strong wind.

Stratospheric Nacreous Cloud
June 2011. Warm and Windy.


Temperatures - at Mawson during June we expect:
  • A maximum temperature about -13.5°C. The average maximum for the month was -11.7°C. The coldest maximum was –19°C and the warmest -0.7°C. 
    • A minimum temperature about -19.5°C. The average minimum for the month was -18.6°C. The coldest minimum was -24.3°C and the warmest -11.1°C.
    The coldest June day on record at Mawson was on 26th June 1982 when the minimum fell to -34.0°C.

    Wind:
    • The average daily wind run (the measure of how many kilometres of wind pass the station in 24 hours) was 1078km each day. This was above the long term average of 994km. It falls along way short of the highest average daily June wind run for Mawson recorded in Jun 2003 - 1414km. 
    • The maximum wind gust for June was a modest 156km/h from SE recorded on the 3rd June. The record gust for June is 221km/h from SE recorded on the 28th June 1966.
    • 1 day of blizzard conditions was recorded for June, well below the average of 4. There were 19 gale days, 29 days of strong wind and 4 days when snowfall was observed.
    Sunshine:
    During June the sun was below the horizon from 14th to the 29th (16 days). There was no sunshine recorded by the sunshine recorder for all of June which is normal. Although there was no sunlight, twilight for a few hours in the middle of the day was sufficient to move around without the need of a torch.


    Weather Statistics for June.
    Conditions on midwinter’s day were perfect with light winds, a bright twilight and temperatures ranging -13°C and -19°C.

    Standing waves of stratus cloud.
    July 2011. Much warmer than average.
    July was warmer than average by about 4°C and also windier than the long term average. No records were threatened.

    Temperatures - at Mawson during July we expect:
    • A maximum temperature about -14.6°C. The average maximum for the month was -10.8°C. The coldest maximum was –18.3°C and the warmest -6.4°C
    • A minimum temperature about -20.8°C. The average minimum for the month was -17.1°C. The coldest minimum was -25.2°C and the warmest -10.8°C.
    The coldest July day on record at Mawson was on 17th July 1985 when the minimum fell to -36.0°C.

    Wind:
    • The average daily wind run (the measure of how many kilometres of wind pass the station in 24 hours) was 1321km each day. This was well above the long term average of 971km. It falls along way short of the highest average daily July wind run for Mawson recorded in July 1995 - 1702km.
    • The maximum wind gust for July was 163km/h from SE recorded on the 23rd July. The record gust for July is 221km/h from SE recorded on the 26th July 1998.
    • 6 days of blizzard conditions were recorded for July which is the average expected. There were 24 gale days (11 with blowing snow), 31 days of strong wind and 5 days when snowfall was observed.
    Sunshine
    • On the 17th July Mawson recorded 1.4 hours of sunshine after an absence of recording for 6 weeks and a day. Cloud had prevented a recording even though the sun rising above the horizon from the 4th July. Just over 12 hours were recorded for all of July with 4 hours on the 31st July demonstrating a quick return to more normal light levels.
    Weather Statistics for July.

    Fata Morgana Mirage.

    August 2011. Warm conditions prevail.

    August continues the run of winter months with temperatures above average. Temperatures were warmer than average by about 2°C. There were more gale days but August had less wind than average. There was only 1 blizzard day. No records were threatened.

    After a period of light northerly winds on the 21st a sea fog was recorded at the station. This relatively rare event had rime ice accumulating on steel structures. - at Mawson during August we expect:
    Temperatures

    • A maximum temperature about -15.6°C. The average maximum for the month was -13.2°C. The coldest maximum was –20.2°C and the warmest -5.4°C 
    • A minimum temperature about -21.7°C. The average minimum for the month was -19.8°C. The coldest minimum was -26.1°C and the warmest -9.3°C.
    The coldest August day on record at Mawson was on 14th August 1987 when the minimum fell to -35.9°C.

    Wind:

    • The average daily wind run (the measure of how many kilometres of wind pass the station in 24 hours) was 881km each day. This was below the long term average of 967km. It falls along way short of the highest average daily August wind run for Mawson recorded in August 1996 - 1323km. 
    • The maximum wind gust for August was 130km/h from SE recorded on the 2nd August. The record gust for August is 248km/h from ESE recorded on the 7th August 1971.
    • 1 day of blizzard conditions was recorded for August which is well below the average of 7 expected. There were 21 gale days, 30 days of strong wind and 3 days when snowfall was observed.
    Sunshine
    • The return of the sun provided an average 3.7 hours of sunshine per day with 8.5 hours the highest recorded on 28th August.
     
    Weather statistics for August.

      

       Low stratus cloud and approaching sea fog across the sea ice
      

      September 2011 Mawson winter warmer than long term average.

      September is the 5th consecutive month with temperatures above the long term average. Temperatures were warmer than average by a little over 1°C. There were more gale days than average and September was windier than average by about 15%. There was only 2 blizzard days. No records were threatened.

      Temperatures - at Mawson during September we expect:
      • A maximum temperature about -14.3°C. The average maximum for the month was -13.0°C. The coldest maximum was –21.3°C and the warmest -6.0°C
      •  A minimum temperature about -20.7°C. The average minimum for the month was -19.3°C. The coldest minimum was -24.0°C and the warmest -10.3°C.
      The coldest September day on record at Mawson was on 4th September 1982 when the minimum fell to -35.8°C.

      Wind:
      • The average daily wind run (the measure of how many kilometres of wind pass the station in 24 hours) was 1148km each day. This was about 15% above the long term average of 959km. It falls short of the highest average daily September wind run for Mawson recorded in September 1979 - 1397km.
      • The maximum wind gust for September was 158km/h from SE recorded on the 5th September. The record gust for September is 222km/h from SE recorded on the 17th September 1975.
      • 2 days of blizzard conditions were recorded for September which is well below the average of 6 expected. There were 21 gale days, 27 days of strong wind and 2 days when snowfall was observed.
      Sunshine
      The spring equinox occurred on 23rd September marking the day of equal ad and night. After 23rd September the sun day lengths continue to increase until the summer solstice on 22nd December. Sunshine at Mawson for September was an average 4.9 hours per day with 11.1 hours the highest recorded on 22nd September.

      
      Weather Statistics for September.
      
       
      Moonlight through altocumulous cloud
      October 2011 A cooler than average month.

      October broke the run of consecutive warmer than average months with maximum and minimum temperatures about 2 degrees below normal. The number of days with Blizzards, Gales and strong winds was close to average, however there were 2.6 hours of sunshine each day above the monthly average. Mawson was less windy in October than would be expected. No records were threatened.

      Temperatures - at Mawson during October we expect:
      • A maximum temperature about -9.9°C. The average maximum for the month was -12.0°C. The coldest maximum was –16.6°C and the warmest -6.0°C
      • A minimum temperature about -16.4°C. The average minimum for the month was -18.5°C. The coldest minimum was -22.4°C and the warmest -11.3°C.
      • The coldest October day on record at Mawson was on 2nd October 1980 when the minimum fell to -29.0°C.
      Wind: The average daily wind run (the measure of how many kilometres of wind pass the station in 24 hours) was 810km each day. This was about 10% below the long term average of 911km. It falls short of the highest average daily October wind run for Mawson recorded in October 1992 - 1254km.

      • The maximum wind gust for October was 193km/h from SE recorded on the 22nd October. The record gust for October is 208km/h from SE recorded on the 26th October 2007.
      • 2 days of blizzard conditions were recorded for October, one below average. There were 15 gale days, 27 days of strong wind and 2 days when snowfall was observed.
       Sunshine
      October saw the length of day increase dramatically by more than 3 hours over the month to 17.5 hours by the 31st. Sunshine at Mawson for October was an average 10.2 hours per day (2.6 hours above average and double that of last month) with 15.4 hours the highest daily sunshine recorded on 29th October.

      Weather Statistics for October.

      Lenticular (wave like) clouds above the Mawson Plateau

      November 2011 Windy but close to average temperatures.

      November was close to average for maximum temperatures with minimum temperatures about 1 degree warmer than would be expected. For Mawson November was a windy month with the number of days of Blizzards, Gales and Strong Winds above average. There were 30% more Gale days than would be expected. Average wind speed for each hour of the month was 50km/h. At this speed Hobart, about 6000km from Mawson, would take 5 days to reach. During the 5 days, 6th to the 10th, wind persisted at times exceeding 118 km/h (hurricane force) and Hobart could have been reached in less than three days. Due to increased cloudiness there was about 1.5 hours of sunshine less than the monthly average. No records were threatened.

      Temperatures - at Mawson during November we expect:
      • A maximum temperature about -2.7°C. The average maximum for the month was -2.5°C. The coldest maximum was –6.6°C and the warmest +2.9°C
      • A minimum temperature about -8.9°C. The average minimum for the month was -8.0°C. The coldest minimum was -13.6°C and the warmest -2.9°C.
      The coldest November day on record at Mawson was on 1st November 1954 when the minimum fell to -20.0°C.

      Wind:
      • The average daily wind run (the measure of how many kilometres of wind pass the station in 24 hours) was 1211km each day. This was about 25% above the long term average of 927km. It falls short of the highest average daily November wind run for Mawson recorded in November 2004 - 1373km.
      • The maximum wind gust for November was 176km/h from SE recorded on the 8th November. The record gust for November is 204km/h from SE recorded on the 29th November 1973.
      • 3 days of blizzard conditions were recorded for November, one above average. There were 19 gale days compared to 14 expected for November, 30 days of strong wind and 4 days when snowfall was observed. A Strong Wind day has wind in excess of 41 km/h and a Gale is wind in excess of 63 km/h. 
      Sunshine
      • The length of day rapidly increased over the month, by 30th November the sun sets for the last time until 14th January 2012. Sunshine at Mawson for November was an average 7.1 hours per day which is 1.5 hours below average and about 3 hours less than last month. The highest daily sunshine recorded on 26th November was 17.1 hours.

      Snow shower affected by wind shear at lower levels.

      December   2011 Less windy, cooler and sunny.

      December was less windy with colder minimum and maximum temperatures and more clear skies than would be expected. Mawson in December was about 2 degrees below the average minimum temperature and 0.6 degrees below the average maximum temperature. December was less windy than would be expected with no days of Blizzard and less Gale days. The number of Strong Winds days was about average. Due to less cloud throughout the month there was about 3 hours of sunshine each day more than the monthly average. No records were threatened.

      Temperatures - at Mawson during December we expect:
      • A maximum temperature about +2.1°C. The average maximum for the month was 1.5°C. The coldest maximum was –3.0°C and the warmest +6.6°C
      • A minimum temperature about -3.2°C. The average minimum for the month was -5.2°C. The coldest minimum was -11.1°C and the warmest 0.4°C.
      The coldest December day on record at Mawson was on 4th December 2010 when the minimum fell to -11.7°C.

      Wind:
      • The average daily wind run (the measure of how many kilometres of wind pass the station in 24 hours) was 708 km each day. This was about 12% below the long term average of 804km. It falls well short of the highest average daily December wind run for Mawson recorded in December 2007 - 1132km.
      • The maximum wind gust for December was 98km/h from SE recorded on the 1st December. The record gust for December is 191km/h from SE recorded on the 9th December 1960.
      • No blizzard conditions were recorded for December where one would be expected. There were 6 Gale days compared to 9 expected for December, 24 days of strong wind and 4 days when snowfall was observed. A Strong Wind day has wind in excess of 41 km/h and a Gale is wind in excess of 63 km/h. 
      Sunshine
      • The sun did not set through December however the plateau did shade the station for a few hours each night. Daily sunshine at Mawson for December averaged 12 hours per day which is about 3 hours above the 8.8 hours expected. The highest daily sunshine recorded on 12th December was 17.7 hours. Even though the sun didn’t set, its intensity when less than 5 degrees elevation above the horizon is too week to register on the Sunshine Recorder.

      Orographic cloud on North Masson Range with stratus below from katabatic downs slope drainage.
        January 2012 Cooler and more windy.

      January was cooler by about a degree and more windy than we would expect with less sunshine than average. The month was characterised by more strong wind, gale and blizzards days than is normal for the month. No records were threatened.

      Temperatures - at Mawson during January we expect:
      • A maximum temperature about +2.5°C. The average maximum for the month was 1.4°C. The coldest maximum was –1.3°C and the warmest +4.7°C
      • A minimum temperature about -2.7°C. The average minimum for the month was -4.2°C. The coldest minimum was -7.4°C and the warmest 0.3°C.

      The coldest January day on record at Mawson was on 31st January 1994 when the minimum fell to -10.0°C.

      Wind:
      • The average daily wind run (the measure of how many kilometres of wind pass the station in 24 hours) was 904 km each day. This was about 14% above the long term average of 778km. It falls well short of the highest average daily wind run for Mawson recorded in January 1996 - 1138km.
      • The maximum wind gust for January was 150km/h from SE recorded on the 4th January. The record gust for January is 198km/h from SE recorded on the 11th January 1998.
      • Blizzard conditions were recorded on 4 days for January, very much above the zero to one expected. There were 11 Gale days compared to 9 expected for January, 27 days of strong wind and 4 days when snowfall was observed. A Strong Wind day has wind in excess of 41 km/h and a Gale is wind in excess of 63 km/h. 
      Sunshine
      • The end to the polar day came on the 14th January. The sun set for the first time since 1st December when its upper edge remained below the horizon for 45 minutes. By 31st January 17 days later the sun was set for 4hr 46min. Daily sunshine at Mawson for January averaged 7.4 hours per day which is about an hour below the 8.3 hours expected. The highest daily sunshine recorded on 12th January was 17.6 hours.

      Stratus cloud forming into Kelvin Holmholtz waves.

      February 2012 Cooler and more windy.

      February saw the arrival of the 65th ANARE crew. It was cooler and more windy than we would expect with less sunshine than average. The month was characterised by more strong wind, gale and blizzards days than is normal and less snow days. No records were threatened.

      Temperatures - at Mawson during February we expect:
      • A maximum temperature about -1.4°C. The average maximum for the month was -1.7°C. The coldest maximum was –5.2°C and the warmest +2.2°C
      • A minimum temperature about -7.3°C. The average minimum for the month was -7.6°C. The coldest minimum was -11.7°C and the warmest -3.0°C.
      The coldest February day on record at Mawson was on 28th February 1985 when the minimum fell to -17.3°C.

      Wind:
      • The average daily wind run (the measure of how many kilometres of wind pass the station in 24 hours) was 1192 km each day. This was about 20% above the long term average of 947km. It falls short of the highest average daily wind run for Mawson recorded in February 2008 - 1221km.
      • The maximum wind gust for February was 180km/h from SE recorded on the 26th February. The record gust for February is 194km/h from SSE recorded on the 26th February 1999.
      • Blizzard conditions were recorded on 3 days for February, above the zero to one expected. There were 17 Gale days compared to 11-12 expected for February, 29 days of strong wind (that is every day was a strong wind day!)  and 1 day of snowfall was observed. A Strong Wind day has wind in excess of 41 km/h and a Gale is wind in excess of 63 km/h. 
      Sunshine:
      • Daily sunshine at Mawson for February averaged 7.1 hours per day which is below the 7.7 hours expected. The highest daily sunshine recorded on 6th February was 15.6 hours.


       
      Weather data from Bureau of Meteorology, Mawson,  
      Sunrise Tables from http://www.timeanddate.com/worldclock/
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