Melbourne Metropolitan Area, October 2010: Wettest since 1975

Rainfall totals for October in the Melbourne metropolitan area were generally very much above average. Overall, daytime and night-time temperatures were close to average.

Rainfall

Overall, rainfall across the Melbourne area was very much above average this month. In fact, October 2010 was the wettest October since 1975 for most stations. The month was characterised by the frequent passage of rain bearing frontal systems.

Early in the month, most of the Melbourne region recorded widespread rainfall associated with a series of frontal systems. Most stations received about 2 mm on the 5th, whilst on the 7th, rainfall totals ranged from 6 mm at Bundoora up to 31 mm at Moorabbin Airport. Isolated showers were reported at some stations over the following days but it wasn't until the 13th that most stations recorded rainfall again. Most stations in the Melbourne area recorded five days of consecutive rainfall from the 13th to the 17th; 5-day totals ranged from 19.4 mm at Cranbourne Botanic Gardens up to 65.4 mm at Viewbank. On the 23rd, extensive rainfall delivered between 2 mm and 20 mm to stations in the Melbourne area. Notably, the largest falls for October were associated with a front/trough combination on the last weekend of the month bringing 41 mm to 76 mm to stations around Melbourne on the 31st.

The wettest station overall was Ferny Creek (Dunns Hill) with a total of 180.4 mm for the month. Ferny Creek (Dunns Hill) also recorded the single wettest day with 75.6 mm on the 31st. The driest station overall was Avalon Airport with 101.0 mm, even though it still received very much above average rainfall. Some sites had their highest total October rainfall for at least 20 years and some sites had their highest October daily rainfall on record.

Temperature

Maximum temperature

Average maximum temperatures across the Melbourne area were close to normal for October. Only one station recorded an anomaly of more than 1 C (+1.2 C at Melbourne Regional Office), whilst just one station recorded a negative anomaly (-0.1 C at Avalon Airport). All stations recorded their hottest daily maximum temperatures for the month on either the 22nd or 29th, both of which had several rain free days leading up to them which were associated with high pressure systems. All stations, except for Ferny Creek, recorded their coolest maximum temperatures for the month on the 15th after the passage of a cold front.

The hottest single day was the 29th at Avalon Airport with 29.3 C, whereas the warmest days on average, 20.7 C, were recorded at Melbourne Regional Office. Ferny Creek (Dunns Hill) recorded the coolest days on average, 15.5 C, as well as the coldest single day, 9.1 C on the 16th.

Minimum temperature

Average minimum temperatures across the Melbourne area were close to normal for October. Only one station recorded an anomaly of more than 1 C (+1.4 C at Melbourne Regional Office). Almost all stations in the Melbourne area recorded their coldest daily minimum temperatures on the 2nd after an almost cloud free night. Avalon Airport recorded the coldest night on the 2nd with just 0.3 C. Coldstream recorded the coolest nights on average at 6.9 C.

Almost every station in the Melbourne area recorded their warmest daily minimum temperature on the 30th after a night of almost complete cloud cover. Melbourne Regional Office recorded both the warmest nights on average, 10.9 C, and the single warmest night, 18.8 C on the 30th.

Wind

The strongest wind gust was 83 km/h at Essendon Airport on the 6th.

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Extremes in October 2010
Hottest day 29.3 C at Avalon Airport on the 29th
Warmest days on average 20.7 C at Melbourne Regional Office
Coolest days on average 15.5 C at Ferny Creek (Dunns Hill)
Coldest day 9.1 C at Ferny Creek (Dunns Hill) on the 16th
Coldest night 0.3 C at Avalon Airport on the 2nd
Coolest nights on average 6.9 C at Coldstream
Warmest nights on average 10.9 C at Melbourne Regional Office
Warmest night 18.8 C at Melbourne Regional Office on the 30th
Wettest overall 180.4 mm at Ferny Creek (Dunns Hill)
Driest overall 101.0 mm at Avalon Airport
Wettest day 75.6 mm at Ferny Creek (Dunns Hill) on the 31st
Highest wind gust 83 km/h at Essendon Airport on the 6th

Record highest October daily rainfall
Highest in October 2010 (mm) Previous highest (mm) Years of record
Scoresby Research Institute 63.6 on the 31st 63.2 on the 21st in 1953 61
Moorabbin Airport 72.0 on the 31st 52.6 on the 16th in 1983 59
Cerberus 61.0 on the 31st 40.0 on the 24th in 2000 21
Cranbourne Botanic Gardens 53.8 on the 31st 46.0 on the 23rd in 1995 21



Highest total October rainfall for at least 20 years
Total for October 2010 (mm) Most recent October this high or higher Years since higher Average for October
Laverton RAAF 115.8 165.4 in 1975 35 57.4
Melbourne Airport 128.8 143.8 in 1975 35 54.9
Melbourne Regional Office 135.2 150.2 in 1975 35 66.3
Moorabbin Airport 163.6 165.4 in 1975 33 71.0
Bundoora (Latrobe University) 122.4 123.9 in 1983 27 65.2
Avalon Airport 101.0 144.0 in 1975 25 49.8



Summary statistics for October 2010
Maximum temperatures (C) Minimum temperatures (C) Rainfall (mm)
Mean Diff
from
average
Highest Mean Diff
from
average
Lowest Total Average Rank of
October
2010
Fraction of
October
average
Avalon Airport 19.5 -0.3 29.3 29th 7.6 -0.2 0.3 2nd 101.0 49.8 v high 203%
Bundoora (Latrobe University) 19.9 +0.4 27.2 22nd 9.0 +0.4 2.5 2nd 122.4 65.2 v high 188%
Cerberus 18.5 +0.3 27.9 29th 8.4 -0.2 1.7 2nd 111.2 69.1 high 161%
Coldstream 19.8 +0.5 26.4 29th 6.9 +0.6 0.7 2nd 135.6 66.1 v high 205%
Essendon Airport 19.6 +0.5 27.4 22nd 8.8 +0.7 2.3 2nd 128.2 61.2 v high 209%
Ferny Creek (Dunns Hill) 15.5 +0.3 23.6 22nd 7.3 +0.1 0.5 16th 180.4 94.7 high 190%
Laverton RAAF 19.4 +0.2 29.1 22nd 8.4 +0.2 1.4 2nd 115.8 57.4 v high 202%
Melbourne Airport 19.4 +0.2 27.2 22nd 8.4 0.0 2.6 2nd 128.8 54.9 v high 235%
Melbourne Regional Office 20.7 +1.1 28.9 22nd 10.9 +1.4 4.7 16th 135.2 66.3 v high 204%
Moorabbin Airport 19.3 +0.2 28.7 29th 9.2 0.0 3.2 2nd 163.6 71.0 v high 230%
Scoresby Research Institute 19.7 +0.8 27.1 22nd 8.4 -0.4 2.4 2nd 147.6 85.9 high 172%
Viewbank (ARPANSA) 20.2 +0.2 27.3 29th 8.8 +0.1 2.7 2nd 148.6 66.9 v high 222%

Notes

A Monthly Climate Summary is prepared to list the main features of the weather in Melbourne Metropolitan Area and Environs 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 Monday 1 November 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 10 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

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