Canberra in July 2012: A variable July features warm days and cold nights

  • Close to normal rainfall, fewer rain days than normal
  • Third warmest July on record for maximum temperatures
  • Coldest July since 2002 for minimum temperatures
  • Persistent spell of cold nights in early July

Close to normal rainfall

Canberra Airport recorded 39 mm of rain during July, close to the July average of 41.4 mm. Thirteen days had rain recorded during the month, close to normal for July (11 days), but only four exceeded 1 mm, the fewest since 2004 (average 6 days). Most of the rain fell on the 11th as a low pressure trough crossed the state, with up to 33 mm recorded at Mt Ginini, while Canberra Airport recorded a 2-day total of 24 mm on the 12th.

Warm days but cold nights

The average maximum temperature at Canberra Airport during July was 13 °C, 1.6 °C above the historical average, associated with generally clear, sunny conditions during the month and a lack of cool days. This is the equal third warmest July on record for Canberra, and the warmest since 13 °C in 1999. Tidbinbilla also recorded its warmest July on record, with an average maximum temperature of 12.1 °C.

No days had a maximum temperature below 10 °C during the month, with the coldest day reaching 10.3 °C on the 10th, well below the historical average of 8 cold days. Only two other years have had no days below 10 °C in July, with the coldest day reaching 10.1 °C in 1999 and 10.4 °C in 1993. Three days reached 15 °C during the month, above the July average of 1-2 days, with a maximum temperature of 16.6 °C on the 13th; this was the hottest July day on record at Tidbinbilla, reaching 17.5 °C.

In contrast, the average minimum temperature at Canberra Airport was -1.1 °C, 1 °C below the historical average and the coldest July since 2002 (-1.1 °C), associated with clear conditions and an increase in cool southerly winds. Nineteen nights dropped below 0 °C during the month, including 5 nights below -5 °C, above the historical average of 3 nights although slightly fewer than 2011 (6 nights). Temperatures dropped to -10 °C at Tidbinbilla on the 10th, its coldest night on record.

The coldest period was at the start of the month, with seven consecutive nights below -4 °C between the 3rd and 9th, including two nights below -6 °C, associated with a period of cool southerly winds. This is only the fourth time that Canberra has recorded such a cold spell, with two similar spells in June 1965, and 8 days below -6 °C in July 1962.

The average temperature at Canberra Airport was consequently 6 °C, 0.3 °C above the historical average. The diurnal temperature range was 14 °C, the largest variability since 14.1 °C in 1997.

See a list of temperature records broken during July.

Other phenomena

Canberra Airport recorded an average of 6.2 hours of bright sunshine during July, above the historical average of 5.8 hours. The prevailing wind direction was northwesterly, with 61% of 3pm winds between NNW and WNW; 29% of 3pm winds were SSE-SSW, a larger proportion of southerly winds than normal for July.

Further information

Media
(03) 9669 4057
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Extremes in July 2012
Hottest day 17.5 °C at Tidbinbilla Nature Reserve on the 13th
Warmest days on average 13.0 °C at Canberra Airport
Coolest days on average 3.1 °C at Mount Ginini AWS
Coldest day -1.9 °C at Mount Ginini AWS on the 1st
Coldest night -10.0 °C at Tidbinbilla Nature Reserve on the 5th
Coolest nights on average -2.6 °C at Mount Ginini AWS
Warmest nights on average -0.9 °C at Tidbinbilla Nature Reserve
Warmest night 7.5 °C at Tidbinbilla Nature Reserve on the 14th
Warmest on average overall 6.0 °C at Canberra Airport
Coolest on average overall 0.4 °C at Mount Ginini AWS
Wettest overall 106.0 mm at Mount Ginini AWS
Wettest day 33.0 mm at Mount Ginini AWS on the 11th
Highest wind gust 67 km/h at Mount Ginini AWS on the 13th
67 km/h at Mount Ginini AWS on the 30th

Record highest July temperature
Highest temperature
in July 2012 (°C)
Previous warmest
for July
Years of
record
Average for
July
Tidbinbilla Nature Reserve 17.5 on the 13th 16.6 on the 31st in 2005 28 10.9



Record highest July mean daily maximum temperature
Mean daily maximum
temperature
for July 2012 (°C)
Previous warmest
for July
Years of
record
Average for
July
Tidbinbilla Nature Reserve 12.1 = 12.1 in 2011 27 10.9



Record lowest July temperature
Lowest temperature
in July 2012 (°C)
Previous coolest
for July
Years of
record
Average for
July
Tidbinbilla Nature Reserve -10.0 on the 5th -9.0 on the 7th in 2006 28 0.2



Summary statistics for July 2012
Maximum temperatures
for July
(°C)
Minimum temperatures
for July
(°C)
Rainfall
for July
(millimetres)
Mean for
July
2012
Diff
from
average
Highest for
July
2012
Mean for
July
2012
Diff
from
average
Lowest for
July
2012
Total for
July
2012
Average
for
July
Rank of
July
2012
Fraction of
July
average
Canberra Airport 13.0 +1.6 16.6 13th -1.1 -1 -6.1 4th 39.0 41.4 average 94%
Mount Ginini AWS 3.1   8.3 24th -2.6   -5.8 4th 106.0
Tidbinbilla Nature Reserve 12.1 +1.2 17.5 13th -0.9 -1.1 -10.0 5th 67.1 83.4 average 80%
Tuggeranong (Isabella Plains) AWS 12.7   16.2 13th -1.2   -6.2 7th 44.0

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.

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 Wednesday 1 August 2012. 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