Victoria in April 2011: Slightly cooler than usual

  • Maximum and minimum temperatures below average in the northeast
  • Minimum temperatures above average in the southwest
  • Rainfall close to average

Rainfall

Monthly rainfall totals across the state were mixed but generally close to average. The Mallee recorded its first month of below average rainfall since July 2010. Some parts along the south coast recorded monthly totals very much above average due to persistent south-westerly flow. The Melbourne Regional Office almost doubled its long-term monthly total recording 101.8 mm. Almost half of that was recorded on the 12th when a low pressure system centred over the state delivered 25-100 mm to much of the Central district and western parts of West Gippsland. The wettest station overall was Foster Hoddle recording 192.8 mm. Some sites had their highest total April rainfall for at least 20 years. The wettest single day was the 11th when Warrnambool Airport NDB recorded 74.6 mm. Some sites had their highest April daily rainfall on record. There is a map of rainfall deciles below.

Maximum temperature

Slow moving high pressure systems characterised the weather experienced this month, with clear skies and cool offshore winds suppressing daytime temperatures. As a result, maximum temperatures were slightly cooler than normal, but still close to average, for much of the state. It was only around the North East district that maximum temperatures were below average. The hottest day was the 9th when Swan Hill Aerodrome recorded 30.9 C. The warmest days on average, 23.5 C, were recorded at Hopetoun Airport and Ouyen (Post Office). The coolest days on average were 7.5 C at Mount Hotham. Mount Hotham also recorded the coldest single day on the 11th with 0.9 C. Some sites had their coldest April day (lowest maximum temperature) on record. There is a map of maximum temperature anomalies below.

Minimum temperature

Monthly minimum temperatures across the state were slightly cooler than usual due in part to the clear skies. It was only in parts of the northeast and southwest that minimum temperatures were significantly different from usual. Minimum temperatures in the southwest were above average whilst minimum temperatures in the northeast were below average. The coldest single night was -3.7 C at Dinner Plain (Mount Hotham Airport) on the 3rd and the coolest nights on average were 1.4 C at Mount Hotham. The warmest nights on average were 13.6 C at Wilsons Promontory Lighthouse and the warmest night was the 9th when Cape Otway Lighthouse recorded 20.0 C. There is a map of minimum temperature anomalies below.

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Extremes in April 2011
Hottest day 30.9 C at Swan Hill Aerodrome on the 9th
Warmest days on average 23.5 C at Hopetoun Airport
23.5 C at Ouyen (Post Office)
Coolest days on average 7.5 C at Mount Hotham
Coldest day 0.9 C at Mount Hotham on the 11th
Coldest night -3.7 C at Dinner Plain (Mount Hotham Airport) on the 3rd
Coolest nights on average 1.4 C at Mount Hotham
Warmest nights on average 13.6 C at Wilsons Promontory Lighthouse
Warmest night 20.0 C at Cape Otway Lighthouse on the 9th
Warmest on average overall 16.6 C at Walpeup Research
Coolest on average overall 4.4 C at Mount Hotham
Wettest overall 192.8 mm at Foster Hoddle
Wettest day 74.6 mm at Warrnambool Airport NDB on the 11th
Highest wind gust 111 km/h at Mount Hotham on the 9th

Maps

Anomaly in mean maximum temperature

Map of Anomaly in mean maximum temperature

Anomaly in mean minimum temperature

Map of Anomaly in mean minimum temperature

Rainfall deciles

Map of Rainfall deciles


Record highest April daily rainfall
Highest daily rainfall
in April 2011 (mm)
Previous wettest
for April
Years of
record
Morwell (Latrobe Valley Airport) 70.0 on the 12th 62.7 on the 21st in 1984 28



Highest total April rainfall for at least 20 years
Total rainfall
for April 2011 (mm)
Most recent April
at least this wet
Years since
wetter
Average for
April
Rochester 74.2 82.4 in 1980 31 30.3
Flemington Racecourse 91.8 133.8 in 1989 20 48.3



Record lowest April daily maximum temperature
Lowest daily maximum
temperature
in April 2011 (C)
Previous coolest
for April
Years of
record
Average for
April
Echuca Aerodrome 11.8 on the 11th 12.2 on the 22nd in 1960 55 22.2
Tatura Inst Sustainable Ag 11.4 on the 11th = 11.4 on the 27th in 2008 47 21.5
Kyabram DPI 10.9 on the 11th 11.4 on the 27th in 1982 46 21.7



Summary statistics for April 2011
Maximum temperatures
for April
(C)
Minimum temperatures
for April
(C)
Rainfall
for April
(millimetres)
Mean for
April
2011
Diff
from
average
Highest for
April
2011
Mean for
April
2011
Diff
from
average
Lowest for
April
2011
Total for
April
2011
Average
for
April
Rank of
April
2011
Fraction of
April
average
Southwest Slopes (South) (district 72)
Albury Airport AWS 21.0 -1.4 27.1 9th 7.8 -0.2 4.0 23rd 26.8 35.4 average 76%
Hume Reservoir 22.0 30th 9.2 -0.8 5.2 23rd 29.4 51.5 average 57%
North Mallee (district 76)
Mildura Airport 23.2 -0.3 30.5 9th 9.6 -0.5 6.2 25th 11.8 18.2 average 65%
Ouyen (Post Office) 23.5 +0.1 29.4 8th 9.4 -0.1 2.0 12th 13.0 21.6 average 60%
Walpeup Research 23.3 +0.5 29.9 8th 9.9 -0.1 4.7 3rd 8.2 22.9 average 36%
South Mallee (district 77)
Hopetoun Airport 23.5 29.8 8th 8.3 2.9 23rd 12.0
Swan Hill Aerodrome 23.3 -0.4 30.9 9th 8.7 -0.1 4.1 23rd 21.4 16.5 average 130%
North Wimmera (district 78)
Nhill Aerodrome 22.2 29.3 8th 8.8 2.9 14th 9.6
Warracknabeal Museum 22.5 +0.1 28.6 8th 8.7 -0.2 4.0 14th 8.0 26.5 low 30%
South Wimmera (district 79)
Edenhope Airport 19.7 28.2 8th 9.0 4.5 1st 35.4
Grampians (Mount William) 12.0 17.9 8th 5.9 1.9 10th 79.0
Horsham Aerodrome 21.7 -0.6 28.6 8th 7.4 +0.5 3.3 17th 16.6 27.5 average 60%
Horsham Polkemmet Rd 21.8 +0.2 28.9 8th 8.0 -0.3 4.0 17th 11.1 31.5 low 35%
Kanagulk 19.9 27.6 8th 8.8 4.5 21st 25.6
Longerenong 22.1 +0.6 28.9 8th 8.0 0.0 2.3 23rd 14.4 29.1 average 49%
Pyrenees (Ben Nevis) 14.8 21.1 8th 8.0 3.8 11th 66.6
Stawell Aerodrome 20.0 -0.8 26.9 8th 9.1 +0.9 4.7 1st 22.4 30.0 average 75%
Lower North (district 80)
Charlton 22.5 28.3 9th 8.1 3.3 23rd 12.8
Echuca Aerodrome 21.7 -0.5 28.6 9th 7.7 -1.7 4.5 23rd 51.2 32.6 high 157%
Kerang 22.4 -0.3 29.0 9th 9.2 -0.2 5.4 23rd 20.8 25.4 average 82%
Kyabram DPI 21.3 -0.4 29.4 9th 7.5 -1.2 3.2 23rd 58.2 36.7 high 159%
Upper North (district 81)
Bendigo Airport 20.3 -0.9 26.7 9th 8.2 +0.6 2.3 23rd 42.6 29.2 high 146%
Shepparton Airport 20.6 -1.9 27.4 9th 7.6 -0.7 3.5 23rd 37.2 32.5 average 114%
Tatura Inst Sustainable Ag 20.6 -0.9 27.5 9th 7.4 -0.8 1.7 23rd 48.6 34.4 high 141%
Yarrawonga 21.9 -1.0 28.7 9th 8.4 -0.4 3.6 24th 21.4 26.7 average 80%
Lower Northeast (district 82)
Beechworth Woolshed 20.5 -1.1 25.0 9th 5.3 -0.8 0.8 24th 36.8 46.3 average 79%
Benalla Airport 20.9 28.1 9th 6.9 1.1 23rd 46.3
Corryong Airport 20.4 24.5 9th 4.5 -0.5 18th 42.0
Dartmouth Reservoir 19.5 -1.2 24.0 9th 7.6 +0.7 3.5 24th 55.4 59.4 average 93%
Hunters Hill 15.8 -0.5 20.2 9th 7.5 -0.8 3.2 11th 67.2 65.0 average 103%
Rutherglen Research 21.2 -0.7 27.6 9th 5.5 -1.6 0.7 24th 24.4 40.1 average 61%
Strathbogie 17.7 -1.1 23.1 9th 4.6 -1.0 -0.1 23rd 51.8 66.2 average 78%
Wangaratta Aero 20.9 -1.6 27.4 9th 6.5 -0.3 1.7 24th 34.6 39.6 average 87%
Upper Northeast (district 83)
Dinner Plain (Mount Hotham Airport) 13.9 -1.0 18.5 1st 1.7 -1.7 -3.7 3rd 20.4 46.7 v low 44%
Edi Upper 20.1 -1.1 24.5 9th 7.8 -0.4 3.8 23rd 47.2 60.5 average 78%
Falls Creek 9.3 -0.5 13.9 7th 2.1 -0.9 -2.3 11th 74.6 81.3 average 92%
Mount Buller 8.6 -1.3 12.7 7th 2.2 -1.5 -2.3 11th 129.8 106.7 average 122%
Mount Hotham 7.5 -0.9 12.4 7th 1.4 -1.2 -2.9 11th 112.2 96.2 average 117%
Omeo 17.6 22.3 9th 3.9 -1.9 23rd 17.2
East Gippsland (district 84)
Combienbar AWS 17.2 -0.4 23.2 9th 9.1 -0.4 6.5 1st 56.8 72.2 average 79%
Gabo Island Lighthouse 19.5 +0.3 22.9 19th 13.3 -0.2 9.5 1st 53.6 83.3 average 64%
Gelantipy 15.5 -1.0 21.4 9th 6.2 -0.7 2.4 23rd 28.6 50.3 average 57%
Lakes Entrance (Eastern Beach Road) 19.6 29.0 9th 9.9 6.7 8th 62.4
Mallacoota 19.3 -0.6 25.1 9th 11.4 -0.1 7.3 1st 56.4 89.5 average 63%
Mount Nowa Nowa 18.4 -0.8 25.6 9th 10.4 -0.2 7.4 23rd 90.4 77.0 high 117%
Orbost 20.1 -0.8 28.6 9th 9.8 -0.8 6.1 1st 74.6 75.7 average 99%
Orbost (Comparison) 20.5 -0.4 28.5 9th 8.5 -0.8 4.6 1st 76.3 73.7 average 104%
Point Hicks (Lighthouse) 19.8 0.0 26.0 9th 12.5 -0.6 9.5 3rd 79.1 84.6 average 93%
West Gippsland (district 85)
Bairnsdale Airport 20.2 -0.5 28.7 9th 7.9 -0.6 4.2 1st 60.0 56.5 average 106%
East Sale Airport 19.7 -0.6 29.3 9th 8.4 -0.2 4.6 18th 54.0 48.2 average 112%
Morwell (Latrobe Valley Airport) 19.7 -0.8 28.1 9th 8.6 0.0 3.7 1st 101.0 58.9 v high 171%
Mount Baw Baw 9.0 -0.8 14.7 8th 3.0 -0.7 -0.7 12th 144.6 141.9 average 102%
Mount Moornapa 17.3 -0.9 26.4 9th 9.6 -0.2 6.7 12th 114.6 81.3 high 141%
Noojee (Slivar) 18.3 -0.5 25.2 9th 7.6 +0.2 4.1 5th 104.6 86.1 average 121%
Pound Creek 19.7 27.6 9th 8.7 3.9 18th 102.6
Wilsons Promontory Lighthouse 17.3 0.0 26.1 9th 13.6 +0.9 11.8 12th 116.6 85.2 high 137%
Yarram Airport 19.4 28.3 9th 7.8 3.2 17th 59.6
East Central (district 86)
Bundoora (Latrobe University) 20.2 -0.3 27.0 9th 9.4 -0.4 5.0 1st 86.8 54.4 high 160%
Cerberus 19.5 -0.2 26.9 9th 9.9 0.0 4.4 11th 83.8 66.5 high 126%
Coldstream 20.1 -0.2 25.3 9th 7.2 +0.6 3.6 11th 87.2 61.3 high 142%
Coldstream Comparison 20.0 25.4 8th 7.1 3.5 11th 87.2
Cranbourne Botanic Gardens 19.4 -0.4 25.5 8th 9.8 -0.4 4.3 11th 100.5 70.7 high 142%
Essendon Airport 20.3 +0.3 27.7 9th 9.6 -0.2 4.6 11th 65.0 55.0 average 118%
Ferny Creek 16.1 21.2 9th 9.8 6.4 23rd 128.0
Ferny Creek (Dunns Hill) 15.9 -0.1 22.0 7th 9.4 0.0 6.1 23rd 116.4 94.7 high 123%
Frankston AWS 19.3 +0.1 25.2 8th 12.4 +0.2 8.6 1st
Melbourne Airport 20.3 0.0 27.6 9th 9.3 -0.9 3.2 11th 43.0 43.8 average 98%
Melbourne Regional Office 21.2 +0.9 27.1 9th 11.7 +0.9 8.2 11th 101.8 57.4 high 177%
Moorabbin Airport 20.1 0.0 26.7 9th 9.8 -0.6 4.5 11th 84.2 63.0 high 134%
Rhyll 19.7 +0.3 24.6 9th 12.7 +0.3 9.9 11th 83.2 62.6 high 133%
Scoresby Research Institute 19.8 -0.1 25.5 9th 9.4 -0.7 4.7 11th 92.4 66.8 high 138%
Viewbank (ARPANSA) 20.5 -0.9 26.9 9th 9.3 -0.7 5.0 11th 119.6 58.3 high 205%
Wallan (Kilmore Gap) 16.4 -0.5 22.6 9th 8.7 0.0 4.9 11th 62.4 56.7 average 110%
Wonthaggi 19.7 +0.1 26.9 9th 10.3 0.0 6.5 1st 117.6 79.3 high 148%
West Central (district 87)
Avalon Airport 20.1 -0.1 27.3 9th 8.7 -0.8 4.4 11th 41.4 37.0 average 112%
Grovedale (Geelong Airport) 20.0 -0.2 27.7 9th 8.9 -0.6 5.0 11th 40.2 45.2 average 89%
Laverton RAAF 20.1 -0.1 26.9 9th 9.3 -0.5 3.5 11th 52.6 45.7 high 115%
Sheoaks 18.8 -0.3 25.2 8th 8.2 -0.5 2.9 11th 33.6 37.8 average 89%
North Central (district 88)
Castlemaine Prison 19.3 -0.8 25.7 9th 8.2 +0.7 2.6 23rd 48.6 41.2 average 118%
Eildon Fire Tower 16.9 -1.5 22.0 7th 8.7 -0.4 5.5 23rd 77.2 42.6 high 181%
Lake Eildon 20.1 -0.7 25.4 9th 7.6 -0.2 3.5 3rd 61.2 59.9 average 102%
Mangalore Airport 20.4 -1.0 27.7 9th 7.7 -0.8 2.3 23rd 36.0 39.3 average 92%
Maryborough 20.7 +0.2 25.9 9th 8.2 -0.1 4.1 23rd 33.5 39.5 average 85%
Redesdale 20.0 -0.4 25.5 9th 6.6 -0.6 1.5 23rd 32.2 40.6 average 79%
Western Plains (district 89)
Ararat Prison 19.8 +0.4 26.3 8th 8.4 +1.2 3.3 26th 38.8 43.1 average 90%
Ballarat Aerodrome 18.0 +0.4 23.3 8th 7.2 -0.3 2.5 23rd 31.2 51.6 average 60%
Westmere 19.7 26.8 27th 7.5 3.4 25th 28.6
West Coast (district 90)
Aireys Inlet 18.9 0.0 26.4 8th 11.8 +0.3 8.3 1st 37.4 50.4 average 74%
Cape Nelson Lighthouse 18.2 +0.2 28.2 7th 12.4 +0.2 6.6 18th 45.6 45.1 average 101%
Cape Otway Lighthouse 17.8 -0.2 25.8 8th 12.8 +1.2 8.2 18th 54.0 71.4 average 76%
Casterton 19.0 26.9 8th 8.8 3.7 1st 45.0
Colac (Mount Gellibrand) 18.3 -0.9 25.0 8th 9.5 -0.3 6.1 23rd 29.0 42.3 low 69%
Dartmoor 19.4 28.0 8th 8.9 3.3 17th 53.6
Hamilton Airport 18.7 -1.2 26.1 8th 8.3 0.0 4.0 1st 68.2 39.6 high 172%
Mortlake Racecourse 19.2 -0.6 26.1 7th 8.3 +0.5 2.6 17th 55.0 44.4 high 124%
Port Fairy AWS 19.0 -0.4 27.7 8th 11.0 +0.3 4.9 18th 88.2 52.7 high 167%
Portland (Cashmore Airport) 18.4 0.0 26.3 8th 10.0 +0.2 2.8 18th 61.4 58.5 average 105%
Warrnambool Airport NDB 19.1 -1.0 26.4 8th 9.3 +0.6 2.7 18th 130.2 55.5 v high 235%
Weeaproinah 15.3 +0.3 21.4 7th 9.1 +0.2 5.8 17th 151.0 154.6 average 98%

Notes

A Monthly Climate Summary is prepared to list the main features of the weather in Victoria 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 1 pm on Monday 2 May 2011. 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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