Tuesday, 4 November 2008 - Monthly Climate Summary for Sydney - Product code IDCKGC15L0

Sydney in October 2008 - Generally warm, but with a significant cold spell.

Summary

Mean maximum and minimum temperatures for October in Sydney were generally above average¹, although as is typical in Spring, these warm temperatures were interrupted by a number of colder spells through the month. Rainfall was generally average or close to average across the Greater Sydney area.

An archive of previous monthly summaries for Sydney - Greater Sydney is also available, as are summaries for other states and many other climate summaries and diagnostics.

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Details

• Close to average rainfall
• Slightly above average mean minimum and maximum temperatures
• The 22nd was the coolest October day since 1978

Rainfall

Most areas in the Greater Sydney area recorded average or close to average rainfall during October. Sydney Observatory Hill received a total of 66.6 mm, which is slightly below the historical average of 76.9 mm but falls within the normal variability of all totals. This is the 4th consecutive year with below average October rainfall. There were 13 days of rain, which was just above the average of 11 days. The majority of the month's rain fell on the 4th, 29th and 30th associated with low pressure troughs and on the 22nd and 23rd associated with a deep, unstable southerly airstream.

Most areas in Sydney received between 45 and 80 mm over the month. The higher totals tended to be in the far western suburbs associated with thunderstorm activity. The highest October total for the general Sydney area was 109 mm at Valley Heights in the lower Blue Mountains, followed by 87 mm at Castlereagh in Sydney's far west. The lowest total was 42 mm at Lidcombe.

See a Sydney map of total rainfall. See a NSW map of rainfall deciles.

Temperatures

Most parts of Sydney experienced above average maximum temperatures for October. Sydney Observatory Hill recorded a mean maximum temperature of 23.2 °C, which is 1.1 °C above the historical average of 22.1°C. This is the 5th consecutive year with above average maximum temperatures in October. Only the far western suburbs recorded below average maximum temperatures - Richmond, averaging 24.6° C was 0.7°C below the historic average.

However, in contrast to the warm conditions was the cold snap on the 22nd, where the maximum temperature reached only 14.3 °C at Sydney Observatory Hill. This was the coldest October day since 1978. At Sydney Airport, the maximum temperature of only 14.0°C was the coldest October day since 1967. Conversely, at the end of the month, the city experienced heat wave conditions with a maximum temperature of 35.0°C at Observatory Hill which is 13°C above the historic average maximum. Sydney Airport recorded a maximum temperature of 37.0 °C, which was the warmest day at that location for nearly 2 years. The high variability of daily temperatures during the month is fairly typical for Spring.

Minimum temperatures across the region were also a little above average. Sydney recorded a mean minimum temperature of 14.5 °C, which is 1.0°C above average. Again, Richmond RAAF was the only site to report below average minimum temperature, with a mean of 10.8°C, compared to the average of 11.0 °C.

Following the cold day on the 22nd, Sydney also experienced a cold night on the 23rd when the temperature fell to 7.9°C at the Observatory Hill site, the lowest October temperature for 21 years. At the new site of Terrey Hills, the minimum of 6.3°C was the lowest for October over the 4 years of record.

See a map of NSW mean maximum temperatures. See a map of maximum temperature anomalies.

See a map of NSW mean minimum temperatures. See a map of minimum temperature anomalies.

Wind

In the morning, Sydney (Fort Dension) experienced the greatest frequency of winds from the westerly direction (37%). This is close to what is expected at this time of year. In the afternoons, the prevailing winds shifted to the E-NE (66% of observations), which is slightly more frequent than the average (61%).

There were 5 windy days in coastal Sydney during October compared to this historical average of 7 windy days. The highest wind gust recorded in the greater Sydney area was 87 km/h at Badgerys Creek on the 6th. On the Illawarra coast just south of Sydney, Bellambi Point recorded a gust of 100 km/h. This was associated with a SW change and the passage of a cold front on the 6th.

Other phenomena

There were 2 thunderstorms reported in the vicinity of Sydney Airport during the month, which is about what is expected for October. These occurred on the 3rd and 4th of the month. However, lightning and very isolated heavy showers occurred over parts of the western suburbs on the 11th. Golf ball size hail was reported in the Blue Mountains (Mt Boyce area) with smaller hail at Springwood and Faulconbridge, due to storms on the 20th. Small hail reached as far east as Kings Langley in Sydney's western suburbs. There was an average of 7.6 hours of sunshine each day at the Airport, which is slightly below the October average of 7.9 hours.

Further information

NSW Climate Services Centre
Bureau of Meteorology
Phone (02) 9296 1555
Email reqnsw@bom.gov.au

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Extremes for the Sydney area

Hottest day Highest temperature	37.0°C at Sydney Airport on the 31st
Warmest days on average Highest mean daily maximum temperature	25.9°C at Penrith Lakes AWS
Coolest days on average Lowest mean daily maximum temperature	22.6°C at Terrey Hills AWS
Coldest day Lowest daily maximum temperature	12.1°C at Terrey Hills AWS on the 22nd
Coldest night Lowest temperature	3.0°C at Camden Airport AWS on the 9th
Coolest nights on average Lowest mean daily minimum temperature	10.4°C at Campbelltown (Mount Annan)
Warmest nights on average Highest mean daily minimum temperature	14.5°C at Sydney (Observatory Hill)
Warmest night Highest daily minimum temperature	22.5°C at Sydney (Observatory Hill) on the 3rd
Wettest overall Highest total rainfall	108.8 mm at Valley Heights (Lower Blue Mountains) 87.0 mm at Castlereagh
Driest overall Lowest total rainfall	42.0 mm at Lidcombe
Wettest day Highest daily rainfall	38.6 mm at Valley Heights on the 14th 28.0 mm at Fairfield City Farm (for 24 hrs to 9am) on 12th
Highest wind gust	87 km/h at Badgerys Creek AWS on the 6th

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Records

Nil records.

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Summaries for the Sydney area

Summary statistics for October 2008
	Maximum temperatures for October (°C)				Minimum temperatures for October (°C)				Rainfall for October (millimetres)
	Mean for October 2008	Diff from normal	Highest for October 2008		Mean for October 2008	Diff from normal	Lowest for October 2008		Total for October 2008	Normal for October	Rank of October 2008	Fraction of October normal
Sydney (Observatory Hill)	23.2	+1.1	35.0	31st	14.5	+1.0	7.9	23rd	66.6	76.9	normal	87%
Sydney Airport	24.0	+1.5	37.0	31st	14.3	+1.2	8.0	23rd	49.2	70.6	normal	70%
Bankstown Airport AWS	24.9	+1.2	35.8	31st	12.2	+0.5	5.5	7th	46.0	60.6	normal	76%
Parramatta	24.6	+0.7	35.4	31st	12.6	+0.7	5.6	7th	61.8	68.7	normal	90%
Penrith Lakes AWS	25.9	+0.2	35.7	3rd	12.6	+0.6	6.5	7th	79.4	58.9	normal	135%
Prospect Reservoir	25.2	+1.6	34.9	31st	12.1	0	5.0	7th	53.5	59.4	normal	90%
Richmond RAAF	24.6	−0.7	34.7	31st	10.8	−0.2	4.2	9th	61.0	57.4	normal	106%
Springwood*	23.8		33.8	27th	11.9		6.0	23rd	77.8	75.8	normal	103%
Terrey Hills AWS*	22.6		34.9	31st	13.0		6.3	23rd	76.4

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

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Notes

Further information

NSW Climate Services Centre
Bureau of Meteorology
Phone (02) 9296 1555
Email reqnsw@bom.gov.au

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