Tasmania in May 2012: Wet with two bursts of heavy rain

May was wetter than usual across almost all of Tasmania after two bursts of heavy rain and several cold fronts. Some areas, mainly in the east and on King Island, had their wettest May on record or their wettest May in more than 20 years. Days were cool while nights were mostly mild. 

  • 67 mm in an hour at St Helens
  • Wettest May day on record for a number of sites
  • No extremely cold nights
  • Hobart's wettest May since 1986

Low pressure systems bring heavy rain

Two complex areas of low pressure moved near Tasmania during May bringing locally heavy rainfalls. The first persisted near the state from late on the 1st until the 5th with the heaviest rain falling on King Island during the afternoon of the 3rd and overnight. Daily totals reached nearly 100 mm in eastern parts of King Island, giving City of Melbourne Bay (97.6 mm), Naracoopa (88.8 mm) and Surprise Bay (52.0 mm) their wettest May day on record. Heavy rain also affected eastern Tasmania with most areas recording 30 to 50 mm and locally heavier falls near the coast. The highest totals were around Bicheno and Swansea with 108 mm falling at Friendly Beaches during the whole event. Woodbridge's 57.6 mm on the 4th was its highest May daily rainfall on record.

Further heavy rain affected Tasmania on the 25th and 26th with widespread totals of 50 to 100 mm in the east. Again, some sites had their highest May daily rainfall total on record with daily totals reaching up to 103 mm at Nugent. Thunderstorms in the northeast during the afternoon of the 25th brought some very intense rainfall; St Helens Aerodrome received 67 mm in just one hour, an intensity expected less than once in 100 years. The rain caused flash flooding along with moderate flooding in the Macquarie River and minor flooding in the South Esk River.

Wet overall

Heavy rainfall around the 3rd and 25th combined with rain from a number of cold fronts during the month to ensure May was wetter than usual across almost all of Tasmania. Several sites, mostly in the east, had their wettest May on record or their wettest May for many years. The highest rainfall total was 426 mm at Mount Read, although the true total was probably higher as it is likely some snow was lost. 

Only a few areas had less than 100 mm, mainly in the Central North, Fingal Valley and Derwent Valley. Flinders Island Airport was by far the driest site, with a total of 33.6 mm. Fingal was the second driest site with 55.0 mm.

Cool days and mild nights

Average daytime temperatures in May were generally near average in coastal areas and below average inland. The 1st and 9th were the only days that reached over 20 °C, peaking at 22.3 °C at Scamander on the 1st. In contrast, temperatures struggled to reach the low teens between the 11th and 13th in a cold southerly airflow with widespread showers and snow to 600 metres behind a cold front. The 12th was especially cold: Mount Wellington only reached -1.8 °C, the coldest day of the month, and a number of sites had their coldest May day in 12 years.

Overall, minimum temperatures for May were near average in the north and one to two degrees warmer than usual in the south. The 2nd, 9th and 22nd were particularly warm for this time of the year with many areas not dropping below 10 °C. Nights were cool between the 12th and 14th, coinciding with the chilly days behind a cold front that crossed the state on the 11th, but many sites in the north and east were colder on the 20th or 29th when winds were light and skies were clear. There were no extremely cold nights; the coldest temperature was -4.0 °C at Fingal on the 29th. May temperatures in Tasmania often drop much lower than this.

Hobart: wettest May since 1986

Hobart was much wetter than usual during May with a total of 92.2 mm, double the long-term average. This made it Hobart's wettest May since 1986, and the tenth wettest May on record. Most of the rain fell in two periods: firstly between the 2nd and 4th and then again from the 23rd to the 26th. Daily totals reached 23.6 mm on the 3rd and 34.6 mm on the 26th; the latter was Hobart's wettest day in over a year.

Though Hobart's average minimum temperature of 8.1 °C was only about a degree warmer than usual, the lack of cold nights was remarkable. A typical May in Hobart has seven nights below 5 °C; this month the lowest temperature was 5.2 °C on the 12th. Since records began 130 years ago, 1988 was the only year there wasn't a May temperature below 5.2 °C. The warmest night was 12.4 °C on the 22nd.

Maximum temperatures in Hobart ranged from 10.7 °C on the 12th to 20.4 °C on the 1st. There were several days below 13 °C, but the average maximum of 15.4 °C was still a degree warmer than usual. 

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Extremes in May 2012
Hottest day 22.3 °C at Scamander on the 1st
Warmest days on average 16.7 °C at Scamander and Bicheno (Council Depot)
Coolest days on average 5.2 °C at Mount Read
Coldest day -1.8 °C at Mount Wellington on the 12th
Coldest night -4.0 °C at Fingal (Legge Street) on the 29th
Coolest nights on average 0.7 °C at Mount Wellington
Warmest nights on average 10.7 °C at Swan Island
Warmest night 15.2 °C at Swan Island on the 2nd
Warmest on average overall 13.4 °C at Swan Island
Coolest on average overall 3.1 °C at Mount Wellington
Wettest overall 426.4 mm at Mount Read *
Driest overall 33.6 mm at Flinders Island Airport
Wettest day 102.8 mm at Nugent (Twilight Valley) on the 26th
Highest wind gust 139 km/h at Maatsuyker Island Lighthouse on the 11th

* 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


Record highest May daily rainfall
Highest daily rainfall
in May 2012 (mm)
Previous wettest
for May
Years of
record
Naracoopa 88.8 on the 4th 70.1 on the 4th in 1948 94
City of Melbourne Bay 97.6 on the 4th 58.2 on the 4th in 1948 77
Levendale 75.2 on the 26th 66.5 on the 30th in 1969 70
Woodbridge 57.6 on the 4th 57.2 on the 27th in 1947 61
Mauriceton (Jordan River) 37.8 on the 26th 34.3 on the 30th in 1969 47
Launceston (Ti Tree Bend) 47.2 on the 26th 40.0 on the 26th in 1987 33
Risdon Vale (Poplar Road) 54.8 on the 26th 47.5 on the 3rd in 1973 33
Bull Bay (Lauriston) 35.0 on the 26th 30.0 on the 22nd in 2003 29
Nugent (Twilight Valley) 102.8 on the 26th 80.4 on the 19th in 1986 29
Surprise Bay 52.0 on the 4th 39.9 on the 9th in 1910 29
Tea Tree (The Point) 44.2 on the 26th 44.0 on the 22nd in 2003 27
Campbell Town (Elizabeth R) 63.6 on the 26th 43.7 on the 3rd in 1973 26
Llewellyn (South Esk River) 41.0 on the 26th 34.0 on the 19th in 2007 20



Record highest total May rainfall
Total rainfall
for May 2012 (mm)
Previous wettest
for May
Years of
record
Average for
May
Risdon Vale (Poplar Road) 129.0 115.6 in 1973 33 40.6
Bull Bay (Lauriston) 119.6 81.8 in 1986 29 40.8
Mount Wellington 185.4 151.0 in 2003 29 65.3
Tea Tree (The Point) 115.8 87.8 in 1986 27 34.7
Campbell Town (Elizabeth R) 112.2 101.1 in 1973 26 38.4

Highest total May rainfall for at least 20 years
Total rainfall
for May 2012 (mm)
Most recent May
at least this wet
Years since
wetter
Average for
May
Premaydena Hatchery 157.6 167.6 in 1956* 55 66.5
City of Melbourne Bay 214.0 230.7 in 1958 54 107.7
Naracoopa 209.8 231.9 in 1958* 52 102.0
Hobart Airport 102.2 112.8 in 1969 43 35.5
Levendale 161.8 206.3 in 1969 43 54.2
Orford (Aubin Court) 159.6 223.2 in 1969 43 58.5
York Plains (Handroyd) 120.2 125.6 in 1969 43 42.6
Rotherwood 112.4 122.4 in 1973 39 39.4
Bothwell (Cluny) 113.0 124.1 in 1973* 38 43.2
Dover 122.0 138.2 in 1975 37 71.0
Geeveston (Cemetery Road) 134.2 175.8 in 1975* 34 70.7
Tooms Lake (Tooms River) 158.6 311.1 in 1969* 32 53.5
Huonville (Tutton Avenue) 120.4 148.7 in 1973* 30 58.1
Woodbridge 169.0 189.5 in 1960* 28 69.7
Hobart (Ellerslie Road) 92.2 92.4 in 1986 26 46.5
Lake Leake (Elizabeth River) 121.6 165.4 in 1986 26 73.1
Lunawanna 139.4 158.0 in 1986 26 73.1
Marrawah 170.0 181.6 in 1988 24 104.1
Taroona (Taroona Crescent) 104.2 116.8 in 1986* 24 44.3
Cape Grim BAPS (Comparison) 151.6 234.4 in 1988* 22 76.7
Fort Direction 84.2 85.8 in 1986* 22 42.5

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




Summary statistics for May 2012
Maximum temperatures
for May
(°C)
Minimum temperatures
for May
(°C)
Rainfall
for May
(millimetres)
Mean for
May
2012
Diff
from
average
Highest for
May
2012
Mean for
May
2012
Diff
from
average
Lowest for
May
2012
Total for
May
2012
Average
for
May
Rank of
May
2012
Fraction of
May
average
Northern (district 91)
Bridport (Sea View Villas) 16.0 +0.1 19.1 1st 7.6 -0.2 1.8 13th 111.1 62.0 high 179%
Burnie (Round Hill) 16.0 +0.7 20.1 1st 8.7 +0.4 5.5 12th 89.3 92.6 average 96%
Cape Grim 14.1   17.8 1st 10.0   6.4 4th 143.8
Cape Grim BAPS (Comparison) 14.4 -0.2 18.5 9th 10.0 -0.2 6.5 3rd 151.6 76.7 high 198%
Cressy Research Station 14.7 -0.1 18.7 9th 4.1 +0.8 -2.5 20th 109.4 43.9 v high 249%
Devonport Airport 15.7 +0.4 18.7 1st 6.6 -0.1 1.0 29th 84.2 72.9 average 116%
Launceston (Ti Tree Bend) 15.9 +0.1 20.3 1st 4.9 -0.2 -0.4 20th 94.2 62.2 high 151%
Launceston Airport 14.8   19.4 1st 4.2   -2.4 29th 121.4
Low Head 15.5 +0.1 18.1 9th 9.7 +0.4 4.5 29th 102.4 57.8 high 177%
Luncheon Hill (Forestry) 12.1 -0.9 17.0 1st 6.7 -0.2 3.4 24th 161.8 154.9 average 104%
Marrawah 14.2 -0.5 19.2 1st 9.4 +0.3 5.5 4th 170.0 104.1 v high 163%
Scottsdale (West Minstone Road) 14.6 -0.3 18.4 1st 5.4 -0.5 -0.2 13th 121.4 97.1 average 125%
Sheffield School Farm 13.9 +0.3 17.8 9th 5.6 +0.2 2.2 20th 105.6 81.1 high 130%
Smithton Aerodrome 15.0 -0.4 19.1 9th 6.6 +0.4 0.8 4th 108.8 80.2 high 136%
Wynyard Airport 15.5 +0.4 19.2 9th 5.8 +0.6 0.3 29th 94.4 96.8 average 98%
East Coast (district 92)
Bicheno (Council Depot) 16.7 +0.2 22.0 9th 8.3 -0.2 5.6 21st 128.5 56.8 v high 226%
Eddystone Point 16.6 +0.8 20.0 9th 9.2 -0.5 4.0 13th
Fingal (Legge Street) 15.2 0.0 20.9 9th 2.8 0.0 -4.0 29th 55.2 50.1 average 110%
Friendly Beaches 16.4 +0.3 21.8 9th 8.1 -0.1 3.8 29th 193.2 56.8 high 340%
Lake Leake (Elizabeth River) 11.3 -0.1 15.9 9th 2.7 +0.6 -2.4 29th 121.6 73.1 high 166%
Maria Island (Point Lesueur) 15.3   18.6 9th 9.6   6.3 13th 151.6
Orford (Aubin Court) 15.4 -0.3 19.1 1st 6.3 +0.1 1.2 29th 159.6 58.5 v high 273%
Scamander 16.7 +0.1 22.3 1st 6.9 -0.6 3.0 12th 145.4 53.9 v high 270%
St Helens Aerodrome 16.4 +0.4 20.8 1st 6.9 -0.2 1.7 13th 178.2 46.6 v high 382%
Swan Island 16.1 +0.3 20.4 1st 10.7 0.0 5.2 14th 74.2 46.6 high 159%
Swansea (Francis Street) 16.3   22.0 9th 6.6   1.7 29th 114.8
Midlands (district 93)
Ross (The Boulevards) 14.0 -0.3 19.5 1st 3.9 +0.7 -2.5 20th 114.2 29.7 v high 385%
Southeast (district 94)
Bull Bay (Lauriston) 14.9 -0.1 19.0 1st 9.0 +1.0 4.9 13th 119.6 40.8 highest 293%
Campania (Kincora) 15.6 -0.3 20.7 1st 6.6 +0.9 1.8 31st 103.8 32.1 v high 323%
Cape Bruny (Cape Bruny) 14.0 -0.3 18.1 9th 8.9 +0.3 4.8 13th 140.0 61.2 v high 229%
Cape Bruny Lighthouse 13.9 +0.4 17.6 9th 9.3 +1.0 7.2 14th 136.2 84.4 high 161%
Dover 14.3 -0.4 17.8 8th 7.0 +1.2 2.8 1st 122.0 71.0 v high 172%
Dunalley (Stroud Point) 15.3   21.0 1st 8.9   5.9 5th 100.8
Geeveston (Cemetery Road) 13.8 -0.8 17.8 8th 6.5 +1.9 1.9 31st 134.2 70.7 v high 190%
Grove (Research Station) 14.5   20.5 1st 5.0   -1.5 29th 114.4
Hobart (Ellerslie Road) 15.4 +1.0 20.4 1st 8.1 +1.1 5.2 12th 92.2 46.5 v high 198%
Hobart Airport 15.4 +0.2 21.8 1st 7.3 +0.7 3.3 6th 102.2 35.5 v high 288%
Maatsuyker Island Lighthouse 12.6 -0.2 18.5 1st 8.8 +0.4 4.8 13th 166.8 115.0 high 145%
Melton Mowbray (North Stockman) 13.6 -0.6 18.3 9th 5.4 +1.1 0.6 6th 89.4 29.1 v high 307%
Mount Wellington 5.4 -0.2 10.0 1st 0.7 +0.1 -3.6 13th 185.4 65.3 highest 284%
Tasman Island 13.0 -0.2 16.0 1st 8.5 -0.1 3.1 13th 200.2 70.8 v high 283%
Tunnack Fire Station 12.0 -0.4 16.9 9th 3.9 +0.3 -1.1 4th 143.8 46.3 v high 311%
Derwent Valley (district 95)
Bushy Park (Bushy Park Estates) 15.2 +0.9 17.8 9th 5.3 +1.2 -0.2 31st 80.6 45.4 high 178%
Maydena Post Office 12.3 -0.8 17.8 1st 5.5 +1.2 2.2 13th 113.6 93.5 average 121%
Ouse Fire Station 14.7 -0.2 20.0 1st 5.1 +1.4 -0.6 31st
Tarraleah Village 10.4 -0.7 15.4 8th 4.1 +1.6 -1.2 29th 154.5 101.6 high 152%
Central Plateau (district 96)
Butlers Gorge 9.5 -0.4 14.8 1st 3.4 +1.7 -1.8 29th 180.6 158.6 high 114%
Lake St Clair National Park 9.0 -1.3 13.9 1st 2.9 +1.3 -3.1 29th 201.0 159.0 high 126%
Liawenee 7.8 -1.3 13.3 9th 1.2 +1.2 -2.3 29th 118.8 77.7 high 153%
West Coast (district 97)
Cape Sorell 14.1 +0.4 18.7 8th 9.9 +0.9 6.3 24th 169.4 128.7 high 132%
Hartz Mountain (Keoghs Pimple) 7.2 -1.4 14.4 8th 3.2 -0.2 -1.1 13th 135.8 73.3 v high 185%
Low Rocky Point 13.9   20.6 1st 9.3   5.3 13th 194.8 130.9 high 149%
Mount Read 5.2 -1.2 9.5 1st 1.7 -0.5 -1.9 13th
Scotts Peak Dam 10.8 -0.8 19.7 1st 6.0 +0.4 1.2 13th 282.6 170.3 high 166%
Strahan Aerodrome 13.7 -0.5 20.0 1st 8.2 +0.9 2.5 4th 199.6 144.9 high 138%
Strathgordon Village 10.8 -0.7 18.5 1st 6.5 +1.2 3.0 13th 270.4 240.7 high 112%
Warra 10.4   15.8 1st 4.9   0.6 13th 180.0
King Island (district 98)
King Island Airport 15.0 -0.5 19.2 1st 10.2 +1.0 7.4 7th 122.4 85.6 high 143%
Flinders Island (district 99)
Flinders Island Airport 16.2 0.0 21.0 1st 9.5 +0.5 1.2 14th 33.6 77.9 low 43%
Antarctica and Macquarie Island (district 300)
Macquarie Island 6.1 +0.2 8.0 6th 2.6 +0.1 -1.6 30th 100.6 83.0 high 121%


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 9 am on Friday 1 June 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

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