Tuesday, 1 June 2010 - Monthly Climate Summary for ACT Monthly Summary - Product code IDCKGC25R0
ACT Monthly Summary in May 2010
A wet end to Autumn
- Wettest May since 1995; 10th wettest on record
- Above average mean temperatures
- 15th warmest may on record for maximum temperatures
An archive of previous monthly summaries for ACT Monthly Summary is also available, as are summaries for other states and many other climate summaries and diagnostics.
Returning to the wetter conditions experienced in February and March, Canberra recorded 79.4mm of rainfall in May 2010, almost twice the May average of 44.1mm. This is the wettest May recorded in Canberra since 1995 (137.4mm), and the 10th wettest May on record. Rainfall was highest at Mt Ginini, which recorded 99mm throughout the month.
The rain fell over 9 days, which is similar to the historical average of 8.3 days. However, four of these exceeded 10mm, well above the average of 1.4 heavy rain days, with a maximum fall of 20.8mm on the 30th, associated with an East Coast Low off the NSW coast between the 30th and 31st. Of the two remaining high-rain days, one was associated with the passage of a cold front on the 5th, which brought 19.6mm to Canberra Airport and 28.0mm to the Australian Botanical Gardens, the highest rainfall recorded anywhere in Canberra during the month. The final and smallest high rain day was 11.2mm on the 26th, associated with the passage of a low pressure system.
The mean daily temperature in Canberra during May 2010 was 9.9°C, which was 0.5°C above the historical average for May. This was associated with well above average maximum temperatures, particularly during the first half of the month, but closer to average minimum temperatures.
Maximum temperatures at Canberra Airport were 16.6°C during the month, 1.1°C above the historical average of 15.5°C and the 15th warmest on record. These were due to prevailing high pressure systems and northerly winds during the first half of the month, with temperatures between the 1st and 16th averaging 17.9°C, significantly above average for May. Cool changes in the last two weeks of the month associated with rain-bearing systems decreased the average temperature; however, it remained well above average for May. The warmest daily maximum recorded anywhere in Canberra during the month was 22.5°C at Canberra Airport on the 4th.
In comparison, minimum temperatures averaged 3.1°C during May, only slightly below the historical average of 3.2°C. These were associated with very low overnight temperatures during the middle of the month, with five consecutive days below 0°C between the 12th and 16th, the coldest consecutive May period since 2004. Temperatures reached -3.7°C on the 13th, the lowest May air temperature at Canberra Airport since May 29 2006 (-3.9°C). Nights were slightly warmer at Tidbinbilla, averaging 3.6°C, with the lowest temperature recorded anywhere in Canberra -4.8°C at Mt Ginini AWS on the 12th.
Canberra was dominated by northerly to westerly winds during May, forming 71% of afternoon winds, compared to a historical frequency of 60% from these directions. The highest winds during the month were recorded on the 30th, associated with the passage of an East Coat Low, with maximum wind gusts up to 87 km/h at Mount Ginini AWS (elev 1760m) and 65km/h at Tuggeranong in the city.
Canberra averaged 6.6 sunshine hours during May, slightly above the average of 6.0 hours. One thunderstorm was observed at Canberra Airport, equal to the historical average. Frost was observed on 3 days in the middle of the month, associated with very low minimum temperatures, with fog recorded on 6 days.
22.5 °C at Canberra Airport on the 4th|
|Warmest days on average|
Highest mean daily maximum temperature
16.6 °C at Canberra Airport|
16.6 °C at Tuggeranong (Isabella Plains) AWS
|Coolest days on average|
Lowest mean daily maximum temperature
7.6 °C at Mount Ginini AWS|
15.6 °C at Tidbinbilla Nature Reserve
Lowest daily maximum temperature
1.4 °C at Mount Ginini AWS on the 5th|
-4.8 °C at Mount Ginini AWS on the 12th|
-3.7 °C at Canberra Airport on the 13th
|Coolest nights on average|
Lowest mean daily minimum temperature
1.0 °C at Mount Ginini AWS|
2.9 °C at Tuggeranong (Isabella Plains) AWS
|Warmest nights on average|
Highest mean daily minimum temperature
3.6 °C at Tidbinbilla Nature Reserve|
Highest daily minimum temperature
9.9 °C at Tuggeranong (Isabella Plains) AWS on the 29th|
Highest total rainfall
99.0 mm at Mount Ginini AWS|
79.4 mm at Canberra Airport
Highest daily rainfall
28.0 mm at Canberra (Australian National Botanic Ga on the 5th|
|Highest wind gust||
87 km/h at Mount Ginini AWS on the 30th|
65 km/h at Tuggeranong (Isabella Plains) AWS on the 30th
This table is very wide and may not fit if printed.
|Summary statistics for May 2010|
|Mount Ginini AWS||7.6||13.5||2nd||1.0||-4.8||12th||99.0|
|Tidbinbilla Nature Reserve||15.6||+0.3||21.0||3rd||3.6||-0.1||0.0||7th||70.4||66.3||average||106%|
As of March 2010, the official station for Canberra is 70351 'Canberra Airport'. Averages from the previous site, 70014 Canberra Airport Comparison, are used for comparisons.
This statement has been prepared based on information available at 10 am on Tuesday 1 June 2010. 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
(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.