Tasmania in April 2012: Very warm, especially at the start

April 2012 was much warmer than usual despite a couple of cold periods around the 9th and 29th. Several sites had their warmest start to April on record during the first six days. Most areas had near average rainfall, although the southeast was drier than usual with less than 30 mm falling at many locations.

  • Record warm April days for Hobart
  • 67 mm in 90 minutes at Maatsuyker Island
  • Waves to 15 metres in the west on the 29th
  • Chilly -4.3 °C at Ross on the 30th

A record warm start

Several sites around the state had their warmest start to April on record between the 1st and 6th. Daytime temperatures averaged 3 to 6 degrees warmer than usual for this time of the year, peaking at 29.1 °C at Ouse on the 5th, while overnight temperatures were 1 to 4 degrees above average after a couple of cool nights in some areas. The warmth was caused by a deep low pressure system well to the south of the Bight that combined with a ridge of high pressure over the Tasman Sea to direct a warm, generally northwesterly airflow over Tasmania.

Cold at times, but much warmer than usual overall

The coldest part of the month occurred between the 7th and 10th when several cold fronts crossed the state and southwesterly winds prevailed. Mount Wellington only reached -0.7 °C on the 9th as snow fell to around 600 metres, and Ross dropped to -4.0 °C early on the 10th. 

Warmer conditions returned on the 11th, and temperatures remained mostly above average until near the end of the month. A moist northeasterly airstream between the 19th and 21st brought the warmest nights, peaking on the 20th when Devonport (17.4 °C) and Maydena (14.0 °C) both had their highest April minimum temperature on record. Flinders Island had the two warmest nights of the month with 18.2 °C on the 20th and 17.9 °C on the 19th.

A cold front on the 28th brought a wintery end to the month with much cooler than usual temperatures, showers, snow to around 800 metres, destructive winds and large swells. The waverider near Cape Sorell reached 15.3 metres early on the 29th and swells reached 8 metres at Maatsuyker Island and 6 metres at Cape Bruny. It was cold and frosty on the morning of the 30th with the temperature at Ross falling to -4.3 °C.

On average, both maximum and minimum temperatures were up to two degrees warmer than usual for April. Some sites had their warmest average April maximum or minimum temperature on record.

A few bursts of rain and several thunderstorms

Tasmanian rainfall in April mostly came from cold fronts between the 6th and 9th and on the 28th, and low pressure systems between the 19th and 25th. There were thunderstorms on nearly all of these days and quite widespread hail on the 9th and 23rd; this is relatively uncommon for Tasmania. Thunderstorms in the far south early on the 24th brought exceptionally heavy rain to Maatsuyker Island with 67 mm falling in just 90 minutes. Maatsuyker's daily total reached 113 mm, making it their third wettest day in over 100 years, and their monthly total of 206 mm was their highest April rainfall total since 1986. Intense rain also fell at Friendly Beaches on the 20th, with 26 mm recorded in just one hour.

For the whole month, much of the state had near average rainfall. The southeast, including the lower Midlands, was drier than usual with many sites recording less than 30 mm. Dodges Ferry, with just 13.6 mm, was the driest site. The far south had more rain then usual, as did the north around Sheffield and Deloraine where monthly totals exceeded 80 mm. Mount Read was the wettest site, with at least 291 mm falling during the month (it is likely some snow was lost).

Record warm in Hobart

April was especially warm in Hobart with a near-record high average temperature of 15.0 °C (the record is 15.1 °C). Nights averaged at 10.5 °C, over a degree warmer than usual, while days averaged at a record 19.6 °C. The warmth was prominent at the start of the month with an average maximum temperature of 24.5 °C for the first six days. The 14th and 19th were also warm, making six days when the temperature reached at least 24 °C; this hasn't happened before in Hobart in April. 

Despite warm conditions overall, there were still some cold days with snow covering the mountain on the 9th and 29th. The temperature only reached 12.5 °C on the 9th, and dropped to 4.0 °C on the morning of the 30th. In contrast, the warmest night was 16.3 °C on the 20th and the warmest day was 28.9 °C on the 5th. 

Rainfall was well below average with just 22 mm for the month, around 40% of normal. The long-term average for April is 52 mm.

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Extremes in April 2012
Hottest day 29.1 °C at Ouse Fire Station on the 5th
Warmest days on average 20.2 °C at Campania (Kincora)
Coolest days on average 9.5 °C at Mount Read
Coldest day -0.7 °C at Mount Wellington on the 9th
Coldest night -4.3 °C at Ross (The Boulevards) on the 30th
Coolest nights on average 3.1 °C at Liawenee
Warmest nights on average 13.3 °C at Swan Island
Warmest night 18.2 °C at Flinders Island Airport on the 20th
Warmest on average overall 16.0 °C at Swan Island
Coolest on average overall 6.6 °C at Mount Wellington
Wettest overall 290.6 mm at Mount Read **
Driest overall 13.6 mm at Dodges Ferry
Wettest day 113.2 mm at Maatsuyker Island Lighthouse on the 24th
Highest wind gust 150 km/h at Hogan Island on the 7th
** The true total at Mount Read is probably higher, as it is likely some snow was lost.

Maps
Observed Anomaly Decile rank
Total
rainfall
Map of Rainfall totals Map of Percentage of normal rainfall Map of Rainfall deciles
Mean
daily
maximum
temperatures
Map of Mean maximum temperature Map of Anomaly in mean maximum temperature Map of Decile rank of mean maximum temperature
Mean
daily
minimum
temperatures
Map of Mean minimum temperature Map of Anomaly in mean minimum temperature Map of Decile rank of mean minimum temperature

Click on a map to show it full size in a pop-up window



Highest total April rainfall for at least 20 years
Total rainfall
for April 2012 (mm)
Most recent April
at least this wet
Years since
wetter
Average for
April
Maatsuyker Island Lighthouse 206.0 237.6 in 1986 26 108.9



Record highest April mean daily maximum temperature
Mean daily maximum
temperature
for April 2012 (°C)
Previous warmest
for April
Years of
record
Average for
April
Hobart (Ellerslie Road) 19.6 = 19.6 in 1993 130 17.3

Highest April mean daily maximum temperature for at least 20 years
Mean daily maximum
temperature
for April 2012 (°C)
Most recent April
at least this warm
Years since
warmer
Average for
April
Cape Sorell 17.6 17.8 in 1904* 67 15.4
Maatsuyker Island Lighthouse 15.8 16.7 in 1989 23 14.5

* note: there are gaps in the historical record at this site, so it is possible a higher value has gone unreported.



Record highest April daily minimum temperature
Highest daily minimum
temperature
in April 2012 (°C)
Previous warmest
for April
Years of
record
Average for
April
Devonport Airport 17.4 on the 20th 16.7 on the 1st in 1994 21 8.7
Maydena Post Office 14.0 on the 20th 13.4 on the 3rd in 2005 20 5.4



Record highest April mean daily minimum temperature
Mean daily minimum
temperature
for April 2012 (°C)
Previous warmest
for April
Years of
record
Average for
April
Butlers Gorge 5.3 = 5.3 in 1956 49 3.3
Strathgordon Village 8.2 7.9 in 2005 29 6.9
Tarraleah Village 6.1 5.8 in 2010 27 4.1
Lake St Clair National Park 4.7 4.4 in 2010 21 2.8

Highest April mean daily minimum temperature for at least 20 years
Mean daily minimum
temperature
for April 2012 (°C)
Most recent April
at least this warm
Years since
warmer
Average for
April
Lake Leake (Elizabeth River) 5.5 5.7 in 1990 22 4.2



Highest April mean temperature for at least 20 years
Mean daily
temperature
for April 2012 (°C)
Most recent April
at least this warm
Years since
warmer
Average for
April
Cape Sorell 14.8 14.9 in 1939* 32 12.8
Cape Bruny Lighthouse 14.3 14.4 in 1989 23 12.5
Maatsuyker Island Lighthouse 13.3 14.2 in 1989 23 12.0

* note: there are gaps in the historical record at this site, so it is possible a higher value has gone unreported.




Summary statistics for April 2012
Maximum temperatures
for April
(°C)
Minimum temperatures
for April
(°C)
Rainfall
for April
(millimetres)
Mean for
April
2012
Diff
from
average
Highest for
April
2012
Mean for
April
2012
Diff
from
average
Lowest for
April
2012
Total for
April
2012
Average
for
April
Rank of
April
2012
Fraction of
April
average
Northern (district 91)
Bridport (Sea View Villas) 18.7 +0.6 23.8 3rd 10.2 +0.7 2.4 29th 53.5 62.1 average 86%
Burnie (Round Hill) 19.1 +1.4 23.4 3rd 11.2 +1.2 3.8 10th 52.6 74.6 average 71%
Cape Grim 16.8   21.5 5th 12.4   6.8 10th 78.8
Cape Grim BAPS (Comparison) 17.2 +0.8 22.3 5th 12.4 +1.0 6.8 10th 85.4 68.2 average 125%
Cressy Research Station 19.2 +1.0 24.6 3rd 6.3 +0.7 -2.4 30th 44.2 45.3 average 98%
Devonport Airport 18.6 +1.0 21.7 18th 9.1 +0.4 2.0 10th 30.4 61.3 low 50%
Launceston (Ti Tree Bend) 19.6 +0.8 24.5 5th 8.2 +0.7 0.3 10th 37.8 53.1 average 71%
Launceston Airport 19.2   24.6 5th 7.2   -0.6 10th 34.0
Low Head 18.3 +0.7 21.6 5th 12.0 +0.9 6.4 30th 42.6 57.5 average 74%
Luncheon Hill (Forestry) 16.4 +0.8 23.6 5th 9.1 +1.0 2.6 10th 109.6 104.0 average 105%
Marrawah 17.6 +0.8 24.0 5th 11.5 +1.2 6.0 10th 98.6 85.7 average 115%
Scottsdale (West Minstone Road) 18.1 +0.1 24.0 5th 8.1 +0.2 0.8 29th 54.0 80.9 average 67%
Sheffield School Farm 16.9 +0.4 22.4 5th 7.2 +0.2 0.0 10th 99.8 66.5 high 150%
Smithton Aerodrome 18.5 +0.8 22.2 4th 7.8 0.0 1.2 10th 66.2 59.4 average 111%
Wynyard Airport 18.8 +1.4 23.3 3rd 7.8 +0.7 0.2 10th 46.8 73.8 average 63%
East Coast (district 92)
Bicheno (Council Depot) 19.3 +0.5 26.5 15th 11.0 +0.7 4.5 30th 39.6 59.9 average 66%
Eddystone Point 19.7 +1.6 25.7 5th 11.8 +0.3 3.7 10th
Fingal (Legge Street) 19.3 +1.0 27.1 4th 5.4 -0.1 -3.8 30th 40.8 52.0 average 78%
Friendly Beaches 19.4 +0.8 25.9 15th 10.7 +1.0 2.4 30th 70.2 54.4 average 129%
Lake Leake (Elizabeth River) 15.3 +1.2 22.9 5th 5.5 +1.3 -3.0 30th 43.0 69.5 average 62%
Maria Island (Point Lesueur) 18.9   25.1 5th 12.0   5.8 10th 41.6
Orford (Aubin Court)     26.4 6th 8.9 +0.5 2.4 29th 50.6 58.1 average 87%
Scamander 19.3 +0.5 26.6 4th 10.1 +0.3 3.2 30th 36.6 69.0 average 53%
St Helens Aerodrome 19.3 +1.0 25.4 3rd 10.1 +0.5 2.9 30th 32.0 61.1 low 52%
Swan Island 18.6 +0.4 21.9 5th 13.3 +0.5 6.5 10th 38.4 50.3 average 76%
Swansea (Francis Street) 19.5   26.5 15th 9.2   1.0 30th 42.4
Midlands (district 93)
Ross (The Boulevards) 18.8 +1.3 24.6 3rd 6.0 +0.3 -4.3 30th 24.4 37.3 low 65%
Southeast (district 94)
Bull Bay (Lauriston) 18.5 +1.3 25.0 6th 10.4 +0.9 5.4 10th 33.8 48.1 average 70%
Campania (Kincora) 20.2 +1.4 28.3 6th 7.7 +0.4 -0.6 30th 16.6 37.4 low 44%
Cape Bruny (Cape Bruny) 17.5 +1.2 24.7 5th 11.1 +1.3 5.0 9th 87.4 55.2 high 158%
Cape Bruny Lighthouse 17.1 +1.6 23.8 5th 11.2 +1.6 5.2 9th 88.8 80.0 average 111%
Dover 18.0 +1.3 25.0 4th 7.9 +0.8 1.0 30th 76.8 67.5 high 114%
Dunalley (Stroud Point) 19.1   25.9 5th 11.5   5.7 30th 19.2
Geeveston (Cemetery Road) 17.9 +0.7 26.2 5th 7.6 +1.3 -0.4 30th 95.4 65.0 high 147%
Grove (Research Station) 18.7   26.8 5th 5.9   -1.8 30th 61.4
Hobart (Ellerslie Road) 19.6 +2.3 28.9 5th 10.4 +1.5 4.0 30th 22.0 51.4 low 43%
Hobart Airport 19.8 +1.7 27.5 5th 9.2 +0.4 2.5 30th 14.0 43.0 low 33%
Maatsuyker Island Lighthouse 15.8 +1.3 24.3 19th 10.9 +1.4 5.2 9th 206.0 108.9 v high 189%
Melton Mowbray (North Stockman) 18.4 +1.2 26.4 6th 7.1 +1.4 0.4 30th 20.2 30.0 average 67%
Mount Wellington 9.7 +1.3 18.0 5th 3.4 +1.2 -3.1 9th
Tasman Island 16.0 +1.2 23.9 5th 10.7 +1.0 3.9 10th 73.4 70.4 average 104%
Tunnack Fire Station 16.9 +1.7 23.6 6th 6.6 +1.4 -3.2 30th
Derwent Valley (district 95)
Bushy Park (Bushy Park Estates) 19.4 +1.5 28.1 5th 6.2 0.0 -0.8 30th 38.2 46.5 average 82%
Maydena Post Office 16.3 +0.4 25.0 6th 7.1 +1.7 1.5 10th 95.6 83.5 high 114%
Ouse Fire Station 19.1 +0.8 29.1 5th 6.2 +1.4 -0.6 30th 42.4 31.7 high 134%
Tarraleah Village 13.8 -0.1 22.3 6th 5.8 +1.7 -0.9 30th 89.9 95.0 average 95%
Central Plateau (district 96)
Butlers Gorge 13.9 +0.9 22.0 6th 5.3 +2.0 -1.8 2nd 108.6 144.5 average 75%
Lake St Clair National Park 13.6 +0.6 22.1 5th 4.7 +1.9 -1.7 30th 143.4 135.4 average 106%
Liawenee 12.7 +0.5 21.7 5th 3.1 +1.5 -4.2 30th 71.0 73.3 average 97%
West Coast (district 97)
Cape Sorell 17.6 +2.2 22.8 6th 12.0 +1.7 7.0 10th 99.8 110.0 average 91%
Hartz Mountain (Keoghs Pimple) 11.8 +0.8 19.9 6th 5.8 +1.4 -0.6 9th
Low Rocky Point 17.3   28.1 6th 11.2   6.8 9th 141.6 111.5 high 127%
Mount Read 9.5 +0.6 17.4 6th 4.3 +1.0 -1.9 9th
Scotts Peak Dam 15.9 +1.3 24.2 6th 8.1 +1.5 1.7 9th 153.0 127.3 high 120%
Strahan Aerodrome 18.1 +1.5 27.2 6th 9.5 +1.1 4.3 10th 133.2 114.2 average 117%
Strathgordon Village 15.1 +0.9 22.9 5th 8.2 +1.3 2.0 9th 196.6 201.5 average 98%
Warra 14.5   21.9 5th 6.8   0.7 9th 168.2
King Island (district 98)
King Island Airport 18.6 +1.0 27.5 6th 11.2 +0.7 5.9 16th 66.0 57.2 high 115%
Flinders Island (district 99)
Flinders Island Airport 19.4 +0.7 24.5 3rd 11.7 +1.0 1.8 10th 38.4 59.2 average 65%
Antarctica and Macquarie Island (district 300)
Macquarie Island 7.8 +0.9 9.9 20th 4.9 +1.2 -1.8 30th 87.8 93.1 average 94%


Notes

A Monthly Climate Summary is prepared to list the main features of the weather in Tasmania 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 Tuesday 1 May 2012. 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

Media
(03) 9669 4057
Enquiries