Tasmania in August 2011: Record warmth, more flooding in the northeast

Nights were much warmer than average in August 2011, with several sites setting records. Heavy rain and flooding was experienced on two occasions in the northeast, whilst the west of the state was comparatively dry.

  • Record high minimum temperatures
  • Hobart nights record 2.9 C above average
  • Heavy rain and major flooding in the northeast
  • 153 mm in a day at Cornwall
A summary for all of winter has also been prepared.

Record warm August nights

Average minimum temperatures were generally 2 to 3 C warmer than usual, with many sites, including Hobart and Launceston recording their highest August mean daily minimum temperature on record. Most locations had no more than a handful of nights that were cooler than average. This was due largely to slow moving high pressure systems in the Tasman Sea directing mild northerly winds over Tasmania, and reducing the strength of cold fronts reaching the state.

On the 4th, Flinders Island Airport had a record warm night. The 6 am temperature (20.5 C) and 9 am temperature (21.1 C) were August records for those times of the day. The 6 am temperature was also a Tasmanian state record for 6 am in August. It is unusual to get such high morning temperatures that early in August: most of the high August temperatures are later in the month. Some other sites had record warm temperatures on the 10th and around the 18th.

One or two very cold nights

Despite the record warmth, there were a few very cold nights around the 11th and 12th, when subzero temperatures were observed at a number of locations. Strahan recorded its coldest August night on record on the 11th when the temperature dropped to -1.8 C and the coldest night overall was at Liawenee with -7.5 C on the 12th.

Many warm days

On the 4th, temperatures at several locations approached 20 C, and Flinders Island reached 22.2 C on both the 4th and 5th. This is very close to the August state record of 25.0 C at Campania, but this occurred on the 31st in 2006: it is very unusual to have such warm weather so early in August.

The last two weeks of August were also warm as mild northerly winds maintained above average temperatures. A few locations across Tasmania experienced their highest August mean daily maximum temperature on record.

Record warm overall

On many measures, Tasmania had its warmest August on record. Several individual sites had their highest August mean temperature on record. Averaged across the state, maximum temperatures, minimum and mean temperatures were highest on record. The state-wide mean temperature was 9.1 C, which is 2.5 C warmer than average. The previous warmest August was in 1982, when the mean temperature was 8.3 C.

Heavy rain and major flooding in the northeast

August saw major flooding in the northeast of Tasmania, with the region experiencing its fourth significant flooding event for the year from the 7th to the 10th, and then its fifth significant event from the 16th to the 20th.

The 7th to the 10th saw heavy rain fall across the northeast of the state. Rainfall totals for the four days exceeded 100 mm at several sites, resulting in major flooding of the South Esk and Macquarie Rivers, peaking at 9.13 m at Llewellyn, and moderate flooding of the North Esk and St Pauls Rivers. Mount Victoria received 261 mm over the four days, 141 mm of that in one day on the 9th.

From the 16th to the 19th four-day rainfall totals again exceeded 100 mm; Cornwall receiving 153 mm in one day on the 18th. This led to major flooding of the South Esk River, peaking at 9.75 m at Llewellyn, and moderate flooding of the North Esk and Macquarie Rivers.

Several roads were closed with both events, and hundreds of thousands of dollars worth of damage was made to infrastructure. The second event was exacerbated by already wet ground and a high water table following the first flooding event, with landslips and some roads washing away.

Dry in the west

In contrast to the northeast of Tasmania, August rainfall was below average in the west of the state as slow moving high pressure systems kept rain bearing cold fronts at bay. There were still some rain events, with cold fronts delivering rainfall in the first week, and up to 90 mm between the 26th to the 29th.

Hobart: Warmest August nights on record

Minimum temperatures were 2.9 C above average in Hobart this August. The average minimum temperature of 8.1 C is the highest August mean daily minimum temperature on record in Hobart (where standard instruments were installed in 1895), beating the previous record set in 2009 by 0.9 C. There was a distinct lack of cold nights, with the temperature only falling to 5 C or below on 2 days, compared to the average of 15.

Days were noticeably warm too. The maximum temperature exceeded 20 C twice (21.7 C on the 24th and 20.2C on the 25th); this does not normally happen at all in August.  The overall average maximum temperature was 14.7 C which is 1.7 C above the August average.

Hobart received 53.2 mm of rain for the month, which is almost right on the August average, and almost exactly half the amount of rain received in August last year. The wettest day was on the 6th when a cloud band delivered 12.6 mm.

Further information

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Extremes in August 2011
Hottest day 22.2 C at Flinders Island Airport on the 4th and 5th
Warmest days on average 15.8 C at Flinders Island Airport
Coolest days on average 5.4 C at Mount Wellington
Coldest day 0.4 C at Mount Wellington on the 14th
Coldest night -7.5 C at Liawenee on the 12th
Coolest nights on average 0.7 C at Mount Wellington
Warmest nights on average 9.9 C at Swan Island
Warmest night 13.7 C at Cape Sorell on the 25th
Warmest on average overall 12.3 C at Eddystone Point
Coolest on average overall 3.1 C at Mount Wellington
Wettest overall 510.4 mm at Mount Victoria (Una Plain)
Driest overall 35.8 mm at Hobart Airport
Wettest day 141.4 mm at Mount Victoria (Una Plain) on the 9th
Highest wind gust 126 km/h at Maatsuyker Island Lighthouse on the 25th
and at Scotts Peak Dam on the 28th

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


Record highest August daily rainfall

Highest daily rainfall
in August 2011 (mm)
Previous wettest
for August
Years of
record
Memana (Babel Farm) 50.0 on the 7th 48.3 on the 16th in 1965 49



Record highest total August rainfall

Total rainfall
for August 2011 (mm)
Previous wettest
for August
Years of
record
Average for
August
Fingal (Legge Street) 198.0 189.6 in 1984 116 60.6
Scamander 188.6 180.4 in 1984 28 65.3
Mount Wellington 272.6 263.6 in 2010 25 89.2
Mount Victoria (Una Plain) 510.4 466.4 in 1970 20 269.8



Record highest August mean daily maximum temperature

Mean daily maximum
temperature
for August 2011 (C)
Previous warmest
for August
Years of
record
Average for
August
Eddystone Point 15.4 15.0 in 2007 53 13.6
Flinders Island Airport 15.8 15.2 in 1982 49 13.7
Marrawah 13.9 13.7 in 1993 40 12.7
Mount Wellington 5.4 5.3 in 2006 30 2.7
Strathgordon Village 12.3 11.1 in 1999 29 9.9
Wynyard Airport 14.3 = 14.3 in 2009 24 13.2
Dover 14.2 = 14.2 in 1993 21 13.1
Lake St Clair National Park 10.3 9.8 in 1999 20 8.1

Highest August mean daily maximum temperature for at least 20 years

Mean daily maximum
temperature
for August 2011 (C)
Most recent August
at least this warm
Years since
warmer
Average for
August
Maatsuyker Island Lighthouse 12.6 12.7 in 1977 34 11.2
Cape Bruny Lighthouse 13.7 14.0 in 1982 29 11.9
Burnie (Round Hill) 14.4 15.1 in 1982 28 13.1
Tarraleah Village 11.1 11.6 in 1982 28 9.4
Launceston (Ti Tree Bend) 14.8 15.1 in 1982 26 13.8



Record highest August daily minimum temperature

Highest daily minimum
temperature
in August 2011 (C)
Previous warmest
for August
Years of
record
Average for
August
Bushy Park (Bushy Park Estates) 11.9 on the 18th 10.6 on the 25th in 1970 50 2.3
Burnie (Round Hill) 13.3 on the 10th 12.7 on the 30th in 2005 46 6.1
Launceston (Ti Tree Bend) 11.5 on the 18th = 11.5 on the 17th in 1995 29 3.6
Fingal (Legge Street) 11.4 on the 19th 11.1 on the 10th in 2007 26 1.2
Wynyard Airport 12.9 on the 10th 12.4 on the 30th in 2005 25 4.0



Record lowest August temperature

Lowest temperature
in August 2011 (C)
Previous coolest
for August
Years of
record
Average for
August
Strahan Aerodrome -1.8 on the 11th -1.5 on the 15th in 2004 20 5.8



Record highest August mean daily minimum temperature

Mean daily minimum
temperature
for August 2011 (C)
Previous warmest
for August
Years of
record
Average for
August
Hobart (Ellerslie Road) 8.1 7.2 in 2009 116* 5.2
Bushy Park (Bushy Park Estates) 5.4 4.7 in 2009 75 2.3
Maatsuyker Island Lighthouse 8.5 8.1 in 1980 74 6.4
Burnie (Round Hill) 8.6 7.8 in 2009 61 6.1
Eddystone Point 9.1 8.6 in 2009 53 7.2
Hobart Airport 7.4 7.1 in 2009 53 4.7
Orford (Aubin Court) 7.1 6.7 in 2009 43 4.2
Bicheno (Council Depot) 8.2 8.1 in 2007 36 6.3
Scottsdale (West Minstone Road) 6.2 5.6 in 2009 31 3.8
Mount Wellington 0.7 0.2 in 1999 30 -1.8
Strathgordon Village 5.9 5.6 in 1982 29 3.6
Tarraleah Village 3.7 2.8 in 2005 29 0.8
Launceston (Ti Tree Bend) 6.7 6.6 in 2009 28 3.6
Scamander 7.5 = 7.5 in 2009 27 5.2
Fingal (Legge Street) 4.8 4.5 in 2009 25 1.2
Geeveston (Cemetery Road) 5.8 = 5.8 in 2009 24 2.8
Dover 6.7 5.8 in 2009 21 3.9
Lake Leake (Elizabeth River) 4.3 3.2 in 2009 21 0.7
Lake St Clair National Park 2.6 1.9 in 2009 20 0.1
*Note: Hobart's temperature record extends back to 1882, but a standard Stevenson screen was not installed until 1895.

Highest August mean daily minimum temperature for at least 20 years

Mean daily minimum
temperature
for August 2011 (C)
Most recent August
at least this warm
Years since
warmer
Average for
August
Marrawah 8.5 8.6 in 1980 31 7.0
Cape Bruny Lighthouse 7.9 8.0 in 1983 28 6.3



Record highest August mean temperature

Mean daily
temperature
for August 2011 (C)
Previous warmest
for August
Years of
record
Average for
August
Hobart (Ellerslie Road) 11.4 11.3 in 1982 116 9.1
Bushy Park (Bushy Park Estates) 10.3 9.4 in 1982 75 7.7
Maatsuyker Island Lighthouse 10.6 10.2 in 1980 74 8.8
Burnie (Round Hill) 11.5 11.0 in 1982 61 9.6
Eddystone Point 12.3 11.7 in 2009 53 10.4
Hobart Airport 11.0 = 11.0 in 1982 53 9.1
Flinders Island Airport 12.0 11.9 in 1982 49 10.2
Marrawah 11.2 11.0 in 2009 40 9.8
Scottsdale (West Minstone Road) 9.9 9.6 in 1999 31 8.2
Mount Wellington 3.0 2.6 in 2006 30 0.4
Strathgordon Village 9.1 8.4 in 1982 29 6.8
Tarraleah Village 7.4 6.7 in 1982 29 5.1
Launceston (Ti Tree Bend) 10.8 10.5 in 2009 28 8.7
Fingal (Legge Street) 9.4 9.1 in 2009 25 7.2
Geeveston (Cemetery Road) 10.0 9.7 in 2005 24 7.9
Dover 10.5 10.0 in 2005 21 8.5
Lake Leake (Elizabeth River) 7.2 6.6 in 2009 21 5.1
Lake St Clair National Park 6.4 5.2 in 1999 20 4.1

Highest August mean temperature for at least 20 years

Mean daily
temperature
for August 2011 (C)
Most recent August
at least this warm
Years since
warmer
Average for
August
Orford (Aubin Court) 10.8 10.9 in 1982 29 9.1




Summary statistics for August 2011

Maximum temperatures
for August
(C)
Minimum temperatures
for August
(C)
Rainfall
for August
(millimetres)
Mean for
August
2011
Diff
from
average
Highest for
August
2011
Mean for
August
2011
Diff
from
average
Lowest for
August
2011
Total for
August
2011
Average
for
August
Rank of
August
2011
Fraction of
August
average
Northern (district 91)
Bridport (Sea View Villas) 14.3 +0.6 16.2 25th 6.6 +0.8 2.0 30th 93.0 87.6 average 106%
Burnie (Round Hill) 14.4 +1.3 16.9 9th 8.6 +2.5 3.4 12th 123.1 109.9 average 112%
Cape Grim 13.3   15.6 19th 9.3   4.3 11th 123.8


Cape Grim BAPS (Comparison) 13.6 +0.9 16.2 22nd 9.1 +0.8 4.3 11th 121.8 91.6 high 133%
Cressy Research Station 13.6 +0.6 18.4 19th 5.6 +3.2 -1.6 12th 67.2 72.8 average 92%
Devonport Airport 13.9 +0.8 17.3 19th 7.4 +2.4 2.6 12th 90.8 90.4 average 100%
Launceston (Ti Tree Bend) 14.8 +1.0 18.5 19th 6.7 +3.1 1.8 26th 87.4 86.8 average 101%
Launceston Airport 13.6   17.8 19th 6.1   0.8 26th 72.2


Low Head 13.4 +0.3 15.9 19th 9.1 +1.9 5.6 22nd 98.2 81.8 high 120%
Luncheon Hill (Forestry) 12.6 +1.3 17.5 22nd 6.8 +1.8 2.8 30th 180.0 202.7 average 89%
Marrawah 13.9 +1.2 17.5 22nd 8.5 +1.5 3.5 11th 155.6 131.9 average 118%
Scottsdale (West Minstone Road) 13.6 +1.0 16.9 19th 6.2 +2.4 -0.5 11th 118.0 120.6 average 98%
Sheffield School Farm 12.4 +0.8 14.9 24th 5.7 +1.8 -1.8 11th 136.8 130.9 average 105%
Smithton Aerodrome 14.4 +0.7 17.1 24th 6.1 +0.7 -0.6 11th 133.0 117.1 average 114%
Wynyard Airport 14.3 +1.1 16.8 9th 5.9 +1.9 -1.4 11th 145.0 113.6 high 128%
East Coast (district 92)
Bicheno (Council Depot) 15.4 +0.7 22.0 4th 8.2 +1.9 3.2 12th 88.6 51.5 high 172%
Eddystone Point 15.4 +1.8 18.7 24th 9.1 +1.9 4.3 12th 133.2 72.1 high 185%
Fingal (Legge Street) 14.1 +0.8 19.8 4th 4.8 +3.6 -1.5 30th 198.0 60.4 highest 328%
Friendly Beaches 15.0 +0.3 21.4 4th 8.2 +2.0 1.2 12th 107.4 61.0 high 176%
Lake Leake (Elizabeth River) 10.2 +0.8 14.1 4th 4.3 +3.6 -0.9 26th 190.2 79.3 v high 240%
Maria Island (Point Lesueur) 13.8   18.8 4th 9.2   4.8 12th 50.8


Orford (Aubin Court) 14.4 +0.4 19.4 4th 7.1 +2.9 1.8 12th 83.6 62.3 high 134%
Scamander 15.0 +0.2 21.5 4th 7.5 +2.3 3.0 12th 188.6 65.3 highest 289%
St Helens Aerodrome 14.9 +0.6 19.9 4th 7.8 +2.6 1.9 12th 179.8 74.2 v high 242%
Swan Island 14.0   16.3 2nd 9.9   6.8 12th 147.6


Midlands (district 93)
Ross (The Boulevards) 13.4 +0.8 18.6 19th 5.4 +3.1 -2.8 12th 56.8 49.3 average 115%
Southeast (district 94)
Bull Bay (Lauriston) 13.9 +0.6 20.0 24th 8.0 +2.1 2.5 12th 52.5 56.6 average 93%
Campania (Kincora) 15.4 +1.1 21.3 24th 6.4 +2.4 1.8 15th



Cape Bruny (Cape Bruny) 13.8 +1.0 19.8 25th 8.2 +1.6 3.8 12th 54.6 91.3 low 60%
Cape Bruny Lighthouse 13.7 +1.8 19.1 25th 7.9 +1.6 3.9 12th 49.9 93.1 v low 54%
Dover 14.2 +1.1 20.2 25th 6.7 +2.8 0.0 12th 104.4 89.8 average 116%
Geeveston (Cemetery Road) 14.1 +1.2 20.1 25th 5.8 +3.0 0.6 12th 125.0 104.1 average 120%
Grove (Research Station) 14.5   21.0 24th 5.9   -0.5 12th 77.8


Hobart (Ellerslie Road) 14.7 +1.7 21.7 24th 8.1 +2.9 1.7 12th 53.2 53.6 average 99%
Hobart Airport 14.6 +1.2 21.4 24th 7.4 +2.7 2.0 12th 35.8 46.9 average 76%
Maatsuyker Island Lighthouse 12.6 +1.4 16.8 16th 8.5 +2.1 4.7 29th 75.2 123.2 low 61%
Melton Mowbray (North Stockman) 13.4 +0.8 19.4 24th 5.6 +3.0 -3.8 12th 60.4 51.8 average 117%
Mount Wellington 5.4 +2.7 10.8 19th 0.7 +2.5 -3.7 30th 272.6 89.2 highest 306%
Tasman Island 11.9   17.6 4th 7.6   4.0 29th 61.6 81.0 average 76%
Tunnack Fire Station 11.4 +0.8 15.8 19th 4.8 +2.8 -2.6 12th 99.8 66.2 high 151%
Derwent Valley (district 95)
Bushy Park (Bushy Park Estates) 15.2 +2.1 21.5 24th 5.4 +3.1 -1.3 12th 49.0 54.0 average 91%
Maydena Post Office 13.3 +1.4 19.0 25th 5.1 +2.6 -1.5 12th 119.4 153.1 low 78%
Ouse Fire Station 14.6 +1.0 20.8 24th 5.3 +3.3 -1.5 12th 54.2 63.4 average 85%
Tarraleah Village 11.1 +1.7 16.5 24th 3.7 +2.9 -1.9 12th 132.0 127.1 average 104%
Central Plateau (district 96)
Butlers Gorge 10.4 +2.5 16.7 19th 2.7 +2.7 -5.0 12th 154.2 182.5 average 84%
Lake St Clair National Park 10.3 +2.2 16.2 20th 2.6 +2.5 -3.7 12th 163.4 246.7 low 66%
Liawenee 8.2 +1.6 14.2 19th 1.0 +2.2 -7.5 12th 132.0 142.5 average 93%
West Coast (district 97)
Cape Sorell 14.5 +2.4 17.2 21st 9.6 +2.3 4.9 11th



Hartz Mountain (Keoghs Pimple) 8.2 +1.6 14.9 19th 3.1 +1.7 -0.5 30th 136.0 118.1 average 115%
Mount Read 6.3 +2.3 11.2 19th 2.0 +2.0 -2.1 29th 241.5


Scotts Peak Dam 12.6 +2.3 20.4 19th 5.7 +2.3 0.9 29th 163.2 210.8 low 77%
Strahan Aerodrome 14.7 +1.6 18.4 16th 7.4 +1.6 -1.8 11th 92.6 170.4 low 54%
Strathgordon Village 12.3 +2.4 16.2 23rd 5.9 +2.3 -0.4 11th 215.1 290.9 low 74%
Warra 10.8   17.0 25th 4.6   -0.4 12th 206.4


King Island (district 98)
King Island Airport 14.7 +1.1 18.4 3rd 8.5 +0.7 3.3 12th 95.6 117.2 average 82%
Flinders Island (district 99)
Flinders Island Airport 15.8 +2.1 22.2 5th 8.1 +1.5 0.8 8th 77.4 76.1 average 102%
Hogan Island 14.5   20.3 4th 9.7   7.1 30th 40.8


Antarctica and Macquarie Island (district 300)
Macquarie Island 4.9 -0.1 7.7 23rd 1.3 -0.3 -4.6 14th 72.8 73.1 average 100%

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 11 am on Thursday 1 September 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 the years 1895 to 2100. They are not shown for sites with less than 10 years of record in that time, 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