Monday, 3 March 2008 - Monthly Climate Summary for Sydney extreme rainfall - Product code IDCKGC15x0

Coolest February in 23 years in Sydney

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Details

  • Cool, cloudy month with well below average maximum temperatures
  • Coolest February in 23 years
  • 2nd coolest in last 50 years of record
  • Well above average rainfall
  • Well below average sunshine

Rainfall

The total February rainfall of 258.4 mm at Sydney Observatory Hill was well above the historic February average1 of 117 mm and the wettest February for 6 years. There were 16 rain days during the month, well above the February average of 12 rain days. Above average rainfall occurred throughout the metropolitan area with the heaviest falls in the SW suburbs while the lowest totals were in the far northern suburbs. Above average rainfall occurred throughout the metropolitan area. Monthly totals ranged from 355.8 mm at Liverpool (2nd highest on record) to a low of 186.6 mm at Glenorie.

Prevailing, moist NE to SE airstreams on the NSW coast including Sydney contributed to most of the rainfall. A low pressure trough over Sydney early in the month caused very heavy rain in SW suburbs and some local flash flooding. At Camden, 148.8 mm was recorded on the 5th, the wettest day at that site for 18 years.

The Warragamba Dam catchment recorded moderate to heavy rain during February contributing to further rises in storage levels. Monthly totals over the lower catchment were around 250 mm. However, the upper catchment near Goulburn recorded totals of only 60 - 80 mm. Recent rainfall in Sydney's drinking water catchments can be found on the Sydney Catchment Authority web site http://www.sca.nsw.gov.au/dams/rainfall.html.

Some sites had their highest total February rainfall on record.

Temperatures

Well below average maximum temperatures were recorded over the Sydney metropolitan area during February. The average maximum temperature at Observatory Hill was 24.8°C, which is 1.4°C below the historic1 average maximum. This is the coolest February since 1985 and the 2nd coolest in the last 50 years of record in Sydney. Average maximum temperatures were significantly lower over the remainder of the Sydney region and were the lowest on record at several centres in the west, including Richmond with an average of only 25.6°C or 3.0°C below normal. The main moderating effect on temperatures were the frequent cloudy, wet days, associated with cool onshore winds from SE - NE.

Night-time temperatures were slightly below the historic average over the whole Sydney metropolitan area during February. The average minimum temperature of 18.5°C at Observatory Hill was 0.8°C below the historic1 February average.

The highest temperature at Sydney (Observatory Hill) during February was a mild 29.0°C on the 27th while the lowest overnight temperature was 14.6°C on the 10th. Corresponding extremes in the Sydney metropolitan area ranged from a daytime high of 31.9°C at Richmond on the 22nd to an overnight low of 9.7 °C at Badgerys Creek on the 24th.

Some sites had their lowest February mean daily maximum temperature on record.

Wind

The prevailing direction over coastal Sydney during the day was SW - SE for 50−60% of the time, which is above the normal frequency from this direction. The highest wind gust recorded was 72 km/hr at Sydney Airport on the 29th associated with a strong, cold southerly change.

Other phenomena

Five thunderstorms were reported from the official Sydney city site during February, against an historic average of 3 storms. Between the 2nd and 7th severe storms brought heavy downpours and local flash flooding to many suburbs in the west as well as moderate flooding of the Georges River. Some of the highest hourly falls include 72 mm at Avalon (northern beaches) and 63 mm at Marrickville (inner west) both on the 3rd.

It was a particularly cloudy month with an average daily sunshine of only 5.7 hours per day, well below the historic average of 7.3 hours per day and the lowest since 2002. This is the 3rd lowest average daily sunshine for February over the 30 years of record at Sydney Airport.

Further information

Mike De Salis
Climate Information Officer
NSW Climate Services Centre
Bureau of Meteorology
Phone (02) 9296 1555
Email mikede@bom.gov.au

Extremes for the Sydney area

Hottest day
Highest temperature		 31.9°C at Richmond RAAF on the 22nd
Warmest days on average
Highest mean daily maximum temperature		 26.0°C at Penrith Lakes AWS
Coolest days on average
Lowest mean daily maximum temperature		 23.2°C at Terrey Hills AWS
Coldest day
Lowest daily maximum temperature		 18.4°C at Springwood on the 8th
Coldest night
Lowest temperature		 9.7°C at Badgerys Creek AWS on the 24th
Coolest nights on average
Lowest mean daily minimum temperature		 15.5°C at Campbelltown (Mount Annan) and at Springwood
Warmest nights on average
Highest mean daily minimum temperature		 18.5°C at Sydney (Observatory Hill) and at Sydney Airport
Warmest night
Highest daily minimum temperature		 21.6°C at Sydney (Observatory Hill) on the 3rd
Wettest overall
Highest total rainfall		 355.8 mm at Liverpool
Driest overall
Lowest total rainfall		 186.6 mm at Glenorie
Wettest day
Highest daily rainfall		 148.8 mm at Camden Airport AWS on the 5th
Highest wind gust
 72 km/h at Sydney Airport on the 29th

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Records for the Sydney area

Record highest total February rainfall
Total rainfall
for February 2008 (mm)		 Previous highest
for February		 Years of
record		 Normal for
February
Peakhurst Golf Club
305.0
298.0
in 2002
32
94.8
Campbelltown (Kentlyn)
326.0
257.8
in 2007
29
92.1


Record lowest February mean daily maximum temperature
Mean daily maximum
temperature
for February 2008 (°C)		 Previous lowest
for February		 Years of
record		 Normal for
February
Parramatta
24.9
25.6
in 1996
41
27.9
Bankstown Airport AWS
25.4
25.5
in 1992
40
27.8
Camden Airport AWS
25.4
25.7
in 1992
33
28.6
Richmond RAAF
25.6
26.0
in 1936 and 1956
56
28.6

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Summaries for the Sydney area

Summary statistics for February 2008
Maximum temperatures
for February
(°C)		 Minimum temperatures
for February
(°C)		 Rainfall
for February
(millimetres)
Mean for
February
2008		 Diff
from
normal		 Highest for
February
2008		 Mean for
February
2008		 Diff
from
normal		 Lowest for
February
2008		 Total for
February
2008		 Normal
for
February		 Rank of
February
2008		 Fraction of
February
normal
Sydney 24.8 −1.4 29.0 27th 18.5 −0.8 14.6 10th 258.4 117.9 very high 219%
Camden Airport AWS 25.4 −3.2 30.7 22nd 15.9 −0.8 11.1 29th 287.4 99.2 very high 290%
Parramatta 24.9 −3.0 30.6 22nd 16.5 −1.1 11.6 29th 239.4 125.5 very high 191%
Richmond RAAF 25.6 −3.0 31.9 22nd 16.7 −0.8 11.4 24th 255.6 105.6 very high 243%
Springwood 24.0   29.7 24th 15.5   10.0 29th 228.8 139.2 high 165%
Terrey Hills AWS 23.2   27.3 6th 16.5   11.6 29th 280.6

* new stations, no historic average temperatures available and no historic average rainfall available for Terrey Hills

Additional climate data for Sydney (Observatory Hill) for February 2008
 

February 2008

Normal for February

Number of rain days
16
12

Average sunshine (hours per day)*
5.7
7.3

Average humidity at 3pm (%)
65
64

Number of thunderstorms
5
3

Number of windy days*
7
5
* recorded at Sydney Airport

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Notes

This statement has been prepared based on information available at 5 pm on Monday 3 March 2008. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

1Averages:  historic average temperatures for Observatory Hill and Richmond are based on the period 1961 to 1990 which is a convention of the World Meteorological Organisation.  Average temperatures for Parramatta are based on all available data, 1968 - 2007 and Camden 1972 - 2007.  Rainfall averages and extremes for Observatory Hill are based on all years of record 1859 - 2007.

Normals 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 10 years of record, as they cannot then be calculated reliably.
The median is sometimes more representative than the mean of "normal" 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, normal in decile 4 to 7, high in decile 8 or 9 and very high is in decile 10).
The Fraction of normal shows how much rain has fallen this time as a percentage of the long-term mean.