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.

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

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

Records

Nil records.


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.


Notes

This statement has been prepared based on information available at 9 am on Tuesday 4 November 2008 and updated 10 November. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

1Averages:  historic rainfall and temperature averages are based on all available data.

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 long-term average ("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

.

Further information

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