ACT in March 2011: Cool, humid days and warm nights

  • Equal highest 9am relative humidity on record.
  • Below average rainfall.
  • Coldest March for maximum temperatures since 2001.

Rainfall

Canberra Airport recorded just 41.4mm of rainfall during March 2011, below the historical average of 50.7mm. Daily falls exceeded 10mm only twice during the month, with a maximum daily total of just 13.4mm on the 11th. However, rainfall varied throughout the ACT, with monthly totals as high as 123.4mm at Tharwa General Store, the wettest March at this site since 1989. Much of this was recorded in a single day, with 70 mm recorded to 9am on the 12th, associated with a local thunderstorm. In addition, 30 mm was recorded at Tuggeranong on the 11th and 35 mm at Mt Ginini on the 22nd, significantly wetter than at the airport.

Temperature

Maximum temperatures were cool during March at 23.3 °C, 1.2 °C below the historical average of 24.5 °C. This was the coolest March since 23.2 °C was recorded in 2001, associated with well below average sunshine during the month. No days above 30 °C were recorded during the month compared to a historical average of 3 hot days, with only eight days during the month exceeding 25 °C, the fewest since 1994. However, only three days below 20 °C were recorded during the month compared to the historical average of four days, with a minimum temperature of 19.7 °C.

Minimum temperatures were above average during March at 11.8 °C, 1.1 °C above the historical average of 10.7 °C, resulting in slightly below average mean temperatures during the month. The high minimums were associated with the increased cloudiness during the month in addition to well above average humidity. Only ten days during the month had minimum temperatures below 10 °C at Canberra Airport, below the historical average of 13 days, with a minimum temperature of 3.1 °C on the 31st, the coldest March day since 2005.

Wind

N-W winds prevailed during March, forming 50% of afternoon wind flow, which is normal for March. No strong wind days were reported at Canberra Airport during the month, below the historical average of one day, with a maximum wind gust of just 59 km/hr at the Airport on the 1st, reaching 76 km/hr at Mt Ginini.

Other phenomena

Canberra Airport recorded an average of 6.5 hours of sunshine during March, well below the historical average of 8.1 hours, which ranks as the fourth lowest on record (since 1978). No thunderstorms were reported at Canberra Airport during the month, which is below the historical average of 2 thunderstorms, with only three storms occurring anywhere in the ACT. In addition, no fog was reported at the airport during the month, below the historical average of 2 days.

The average 9am relative humidity was 82% during March, the second highest on record following 83% in March 1982. March 2011 also had the highest number of days on record with relative humidity exceeding 80% at 9am, with 20 days compared to the previous record of 19 days in March 1982, of which 8 exceeded 90%. Despite the cooler maximum temperatures, the average 3pm relative humidity was 54% during March, the third highest on record and the highest since 3pm humidity of 66% in March 1956. Dewpoint temperatures at 9am and 3pm, another measure of humidity, were the highest since March 2000.

Further information

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Extremes in March 2011
Hottest day 29.1 °C at Canberra Airport on the 13th
Warmest days on average 23.3 °C at Canberra Airport
23.3 °C at Tuggeranong (Isabella Plains) AWS
Coolest days on average 14.4 °C at Mount Ginini AWS
Coldest day 7.8 °C at Mount Ginini AWS on the 24th
Coldest night 1.6 °C at Mount Ginini AWS on the 7th
Coolest nights on average 6.9 °C at Mount Ginini AWS
Warmest nights on average 12.5 °C at Tuggeranong (Isabella Plains) AWS
Warmest night 17.9 °C at Canberra Airport on the 14th
17.9 °C at Tuggeranong (Isabella Plains) AWS on the 14th
Warmest on average overall 17.9 °C at Tuggeranong (Isabella Plains) AWS
Coolest on average overall 10.7 °C at Mount Ginini AWS
Wettest overall 125.6 mm at Tharwa General Store
Wettest day 70.0 mm at Tharwa General Store on the 12th
Highest wind gust 76 km/h at Mount Ginini AWS on the 1st

Summary statistics for March 2011
Maximum temperatures
for March
(°C)
Minimum temperatures
for March
(°C)
Rainfall
for March
(millimetres)
Mean for
March
2011
Diff
from
average
Highest for
March
2011
Mean for
March
2011
Diff
from
average
Lowest for
March
2011
Total for
March
2011
Average
for
March
Rank of
March
2011
Fraction of
March
average
Canberra Airport 23.3 -1.2 29.1 13th 11.8 +1.1 4.1 4th 41.4 50.7 low 81%
Mount Ginini AWS 14.4   19.7 13th 6.9   1.6 7th 95.6
Tuggeranong (Isabella Plains) AWS 23.3   29.0 13th 12.5   4.9 4th 78.2

Notes

As of March 2010, the official station for Canberra is 70351 'Canberra'. Averages from the previous site, 70014 Canberra Airport, are used for comparisons.

A Monthly Climate Summary is prepared to list the main features of the weather in ACT Monthly Summary using the most timely and accurate information available on the date of publication; it will generally not be updated. Later information, including data that has had greater opportunity for quality control, will be presented in the Monthly Weather Review, usually published in the fourth week of the month.

This statement has been prepared based on information available at 10 am on Friday 1 April 2011. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

Averages are long-term means based on observations from all available years of record, which vary widely from site to site. They are not shown for sites with less than 20 years of record, as they cannot then be calculated reliably.
The median is sometimes more representative than the mean of long-term average rain.

The Rank indicates how rainfall this time compares with the climate record for the site, based on the decile ranking (very low rainfall is in decile 1, low in decile 2 or 3, average in decile 4 to 7, high in decile 8 or 9 and very high is in decile 10).
The Fraction of average shows how much rain has fallen this time as a percentage of the long-term mean.

Further information

Media
(03) 9669 4057
Enquiries