ACT Monthly Summary in July 2010: Second foggiest July on record

  • Over half monthly rainfall recorded on the 14th July
  • Above average maximum temperatures
  • Foggiest July since 1962

Rainfall

Canberra recorded a total rainfall of 64.8mm in July 2010. This is above the historical average of 41.2mm. The majority of the rain fell over 6 days, which equals the historical average. However over half the total monthly rainfall was recorded at Canberra on the 14th where 38.6mm of rain fell. This was a result of a low pressure trough that moved through South Australia dragging moisture down from the centre of the continent into a rain band that moved across the region. The highest daily rainfall recorded within the ACT was 47.6mm at Tidbinbilla Nature Reserve on the same day. The highest monthly rainfall total was also at Tidbinbilla Nature Reserve, which recorded 77.3mm for the month.

Temperature

The mean daily temperature in Canberra during July 2010 was 6.6 °C, which is 0.9°C above the historical average of 5.7°C.

The mean maximum temperature at Canberra Airport was 12.8°C, 1.5°C above the historical average of 11.3°C. The warmest day was 15.7 °C on the 23rd of the month. Minimum temperatures for July averaged -0.3°C, only slightly below the historical average of -0.1°C. The coldest night recorded at Canberra was -4.5 °C on the 22nd. The warm days and cool nights experienced in Canberra during July were a result of dominant high pressure systems over the area, which brought clear skies and light winds.

Wind

Canberra predominantly experienced north to northwesterly winds, forming 36% of winds, which is average for this time of year. The highest winds during the month were recorded on the 14th, assocated with a cold front which crossed the region on the night of the 13th. The maximum wind gust for July at Canberra (76km/h) was recorded in the early hours of the morning on the 14th.

Other phenomena

Canberra averaged 5.5 hours of sunshine during July, which is below the average of 5.8 hours. There was one Thunderstorm report at Canberra Airport on the 25th. Frost was observed on 21 mornings which equals the historical average. Fogs were observed on 14 mornings making the month the foggiest July since 1962.

 

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Extremes in July 2010
Hottest day 15.7 °C at Canberra Airport on the 23rd
Warmest days on average 12.8 °C at Canberra Airport

Coolest days on average
11.9 °C at Tidbinbilla Nature Reserve
Coldest day -1.4 °C at Mount Ginini AWS on the 14th
Coldest night
-4.9 °C at Mount Ginini AWS on the 3rd
Coolest nights on average -0.3 °C at Canberra Airport
Warmest nights on average 0.3 °C at Tidbinbilla Nature Reserve
Warmest night 9.0 °C at Canberra Airport Comparison on the 31st
Wettest overall 77.3 mm at Tidbinbilla Nature Reserve
Wettest day
38.6 mm at Canberra Airport on the 14th
Highest wind gust
76 km/h at Canberra Airport on the 14th

Summary statistics for July 2010
Maximum temperatures
for July
(°C)
Minimum temperatures
for July
(°C)
Rainfall
for July
(millimetres)
Mean for
July
2010
Diff
from
average
Highest for
July
2010
Mean for
July
2010
Diff
from
average
Lowest for
July
2010
Total for
July
2010
Average
for
July
Rank of
July
2010
Fraction of
July
average
Canberra Airport 12.8   15.7 23rd -0.3   -4.5 22nd 64.8
Canberra Airport Comparison 12.7 +1.4 15.3 23rd -0.1 0.0 -4.2 21st - 40.9 low 51%
Mount Ginini AWS 3.5   6.6 27th     -5.3 2nd 69.0
Tidbinbilla Nature Reserve 11.9 +1.1 14.5 23rd 0.3 +0.1 -3.0 6th 77.3 83.6 average 92%
Tuggeranong (Isabella Plains) AWS 12.8   15.5 31st -0.3   -4.8 21st 53.8

Notes

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 11 am on Monday 2 August 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 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