Tasmania in May 2010: Cool weather arrives, rain in the northeast

After the exceptionally mild start to the year, the cold weather that arrived in Tasmania on May 11 came as something of a surprise and pushed down temperatures for the month. Most of the state had a relatively dry May, but there were some very wet days in the northeast.
  • First significant snow of the year on the 11th
  • Some very cold mornings
  • Localised flooding rain in the northeast on the 28th and 29th

Mild weather replaced by cool

May started mild, with some days reaching into the low 20s and continuing a pattern seen in recent months. This changed when a cold front crossed early on the 11th, bringing with it a blast of chilly air that saw snow settling on the highlands — the first significant snowfall of the year, but one that mostly melted away quickly. Although daytime temperatures recovered a little in the following week, more cool weather followed from about the 20th, especially in the east and south. The final few days were again mild. Taken across the month, daytime maximum temperatures were a fraction above the long-term average in most areas, although a little below average in parts of the inland north.

The warmest day was at Swansea Post Office with 23.4 °C on the 4th, and the warmest days on average were at Bicheno (Council Depot) with 17.2 °C. At the other extreme, the coolest days on average were on the summit of Mount Wellington with 5.4 °C, which also had the coldest day with -0.4 °C on the 21st.

Cold nights

There were several cold nights through the month, with the first taste on the morning of the 3rd when a few spots dipped below zero. The cold change of the 11th heralded a run of cooler nights, with morning fogs and frosts reported. Winds slackened and skies cleared as a high moved over the state late on the 21st, allowing temperatures to plummet on the morning of 22nd. Liaweneedipped to -10.2 °C, the second-coldest May temperature ever recorded in Tasmania (the coldest was -10.5 °C at the same place on 30 May 2006). The 23rd was another cold and frosty morning, and although no significant records were broken several sites had their coldest May temperature for several years.

Taken across the month, overnight minimum temperatures were below average in most areas, typically by half a degree but by almost two degrees in the Upper Derwent Valley and the southern Midlands. Dover had its lowest May mean daily minimum temperature on record, although the record there is only 20 years long so of more significance are Bushy Park and Swansea which had their lowest May mean daily minimum temperature since 1979.

Heavy rain in the northeast

On the 28th the combination of a high to the southeast and a low to the northeast directed very moist and unstable air onto Tasmania's northeast highlands; a "classic" situation for heavy rainfall in that area. Thunderstorms, lightning and hail were reported, and by 9 am on the 29th Gray (Dalmayne Rd) had recorded 191.6 mm, St Marys (Clive Street)  158.4 mm and St Marys (Cullenswood) 143.8 mm, whilst Swansea had its highest May daily rainfall on record with 131.6 mm. Flooding of both streams and rivers was reported, along with damage to roads and other structures. More rain was reported in the area the following day, and ensured that some sites in the area had their highest total May rainfall since at least 1988. The heaviest of the rain was localised, with the southeast, Midlands, Central Plateau and west having just a few millimetres.

Relatively dry overall

Cold fronts and westerly winds brought rain to the west and south for the first two weeks, but the second half of the month had few fronts and mostly only light falls in the west. The southeast also missed out on the bulk of the rain events for the month. Overall, May rainfall totals were below average in most areas. Despite the dry end to the month in the west, the wettest overall was Mount Read with 287.8 mm, but it was closely followed by Gray (Dalmayne Rd) with 263.6 mm, almost all from the heavy rain in the final few days.

Further information

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Extremes in May 2010
Hottest day 23.4 °C at Swansea Post Office on the 4th
Warmest days on average 17.2 °C at Bicheno (Council Depot)
Coolest days on average 5.4 °C at Mount Wellington
Coldest day -0.4 °C at Mount Wellington on the 21st
Coldest night -10.2 °C at Liawenee on the 22nd
Coolest nights on average -0.4 °C at Liawenee
Warmest nights on average 11.8 °C at Hogan Island
Warmest night 15.3 °C at Swan Island on the 10th
Warmest on average overall 13.8 °C at Hogan Island
Coolest on average overall 3.0 °C at Mount Wellington
Wettest overall 287.8 mm at Mount Read
Driest overall 13.0 mm at Richmond (Strathayr)
Wettest day 191.6 mm at Gray (Dalmayne Rd) on the 29th
Highest wind gust 135 km/h at Maatsuyker Island Lighthouse on the 2nd

Maps

ObservedAnomalyDecile 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 2010 (mm)
Previous wettest
for May
Years of
record
Swansea Post Office 131.6 on the 29th 104.9 on the 17th in 1969 107



Highest total May rainfall for at least 20 years

Total rainfall
for May 2010 (mm)
Most recent May
at least this wet
Years since
wetter
Average for
May
Swansea Post Office 154.9 318.6 in 1969 41 47.0
Orford (Aubin Court) 85.0 130.6 in 1988 22 58.0
St Marys (Clive Street) 226.0 379.8 in 1988 21 89.3



Record lowest May mean daily minimum temperature

Mean daily minimum
temperature
for May 2010 (°C)
Previous coolest
for May
Years of
record
Average for
May
Dover 4.5 = 4.5 in 2006 20 5.9

Lowest May mean daily minimum temperature for at least 20 years

Mean daily minimum
temperature
for May 2010 (°C)
Most recent May
at least this cool
Years since
cooler
Average for
May
Bushy Park (Bushy Park Estates) 2.3 1.6 in 1979 31 4.1
Swansea Post Office 5.0 3.9 in 1979 31 6.2




Summary statistics for May 2010

Maximum temperatures
for May
(°C)
Minimum temperatures
for May
(°C)
Rainfall
for May
(millimetres)
Mean for
May
2010
Diff
from
average
Highest for
May
2010
Mean for
May
2010
Diff
from
average
Lowest for
May
2010
Total for
May
2010
Average
for
May
Rank of
May
2010
Fraction of
May
average
Northern (district 91)
Bridport (Sea View Villas) 15.8 -0.1 18.2 10th 7.1 -0.8 2.2 12th 25.2 61.0 low 41%
Burnie (Round Hill) 16.0 +0.7 19.3 3rd 8.9 +0.6 4.2 22nd 60.6 93.7 low 65%
Cape Grim BAPS 15.1 +0.5 17.7 10th 10.0 -0.2 5.5 23rd 54.0 74.4 average 73%
Cressy Research Station 14.4 -0.5 18.4 7th 2.7 -0.8 -5.1 23rd 43.8 39.6 average 111%
Devonport Airport 15.8 +0.5 19.0 10th 6.9 +0.1 1.6 20th 30.4 73.5 low 41%
Launceston (Ti Tree Bend) 15.8 0.0 19.4 7th 4.8 -0.3 -1.6 23rd 46.4 61.8 average 75%
Launceston Airport 14.3   18.9 4th 4.0   -3.1 23rd 36.4


Low Head 15.6 +0.2 17.9 10th 8.9 -0.6 3.5 23rd 27.8 54.5 low 51%
Luncheon Hill (Forestry) 13.6 +0.6 17.5 10th 7.1 +0.1 1.8 22nd 110.8 159.0 low 70%
Marrawah 15.2 +0.5 18.5 10th 8.9 -0.2 4.2 23rd 81.6 103.2 average 79%
Scottsdale (West Minstone Road) 14.5 -0.5 17.5 7th 6.2 +0.3 -0.8 22nd 32.8 98.1 low 33%
Sheffield School Farm 13.4 -0.2 16.4 4th 4.7 -0.9 -0.2 22nd 64.2 82.4 average 78%
Smithton Aerodrome 15.9 +0.5 18.8 9th 6.1 -0.2 -2.4 22nd 74.4 81.5 average 91%
Wynyard Airport 16.0 +0.9 19.4 10th 5.7 +0.4 -2.0 22nd 74.0 98.6 average 75%
East Coast (district 92)
Bicheno (Council Depot) 17.2 +0.7 21.7 7th 8.8 +0.3 3.4 22nd 88.2 56.4 high 156%
Eddystone Point 16.8 +1.0 21.5 4th 9.8 +0.1 3.9 12th 36.2 65.9 low 55%
Fingal (Legge Street) 15.0 -0.3 21.6 4th 2.1 -0.8 -6.4 22nd 96.6 50.2 high 192%
Friendly Beaches 16.4 +0.3 22.9 4th 7.5 -0.8 0.3 23rd 50.8 47.3 high 107%
Lake Leake (Elizabeth River) 11.2 -0.3 16.6 4th 1.7 -0.5 -5.1 23rd 43.6 73.0 average 60%
Maria Island (Point Lesueur) 15.6   21.0 4th 9.6   5.7 23rd 42.6


Orford (Aubin Court) 15.4 -0.4 22.1 4th 5.8 -0.5 0.4 23rd 85.0 58.0 high 147%
Scamander 16.5 -0.1 22.2 4th 7.3 -0.3 1.0 22nd 25.2 51.8 low 49%
St Helens Aerodrome 16.2   21.7 4th 7.4   1.2 22nd 33.4 35.8 average 93%
Swan Island 15.9   20.5 4th 10.7   6.3 21st 31.4


Swansea Post Office 16.3 +0.4 23.4 4th 5.0 -1.2 -1.0 23rd 154.9 47.0 v high 330%
Midlands (district 93)
Ross (The Boulevards) 14.2 -0.2 19.4 4th 2.1 -1.3 -6.5 23rd 17.2 24.5 average 70%
Southeast (district 94)
Bull Bay (Lauriston) 15.2 +0.1 23.0 10th 7.7 -0.4 2.6 23rd 36.4 38.1 average 96%
Campania (Kincora) 16.3 +0.4 22.5 9th 4.1 -1.7 -2.3 22nd 17.8 26.9 low 66%
Cape Bruny (Cape Bruny) 14.8 +0.4 20.8 10th 8.6 -0.1 4.3 23rd 51.6 54.8 average 94%
Cape Bruny Lighthouse 14.5 +1.1 20.5 10th 8.6 +0.3 4.0 12th 67.2 84.0 average 80%
Dover 15.1 +0.3 21.3 10th 4.5 -1.4 -1.0 24th 61.8 70.7 average 87%
Geeveston (Cemetery Road) 14.6 0.0 21.3 10th 3.7 -0.9 -3.3 24th 43.6 70.0 average 62%
Grove (Research Station) 15.2   21.5 10th 2.5   -3.4 23rd 30.6


Hobart (Ellerslie Road) 15.6 +1.2 22.8 10th 6.7 -0.3 1.1 23rd 24.2 46.3 low 52%
Hobart Airport 15.9 +0.7 22.2 10th 6.2 -0.4 1.2 23rd 25.6 34.3 average 75%
Maatsuyker Island Lighthouse 13.5 +0.7 18.9 10th 9.1 +0.7 5.2 12th 87.4 114.9 average 76%
Melton Mowbray (North Stockman) 14.2 -0.1 20.8 10th 2.7 -1.8 -5.1 23rd 24.8 24.8 average 100%
Mount Wellington 5.4 -0.2 10.1 10th 0.6 0.0 -5.9 22nd



Tasman Island 13.3   18.7 10th 8.8   3.9 12th 65.2


Tunnack Fire Station 12.3 -0.2 17.4 9th 2.0 -1.8 -6.8 22nd 34.4 39.2 average 88%
Derwent Valley (district 95)
Bushy Park (Bushy Park Estates) 15.1 +0.8 22.4 10th 2.3 -1.8 -4.9 23rd 19.6 45.3 low 43%
Maydena Post Office 13.2 +0.1 21.0 10th 3.2 -1.2 -3.4 22nd 64.1 94.4 average 68%
Ouse Fire Station 14.4 -0.6 21.2 10th 2.1 -1.8 -4.3 23rd 20.6 31.0 low 66%
Tarraleah Village 11.0 -0.1 18.4 1st 2.4 -0.1 -3.5 22nd 63.3 101.8 average 62%
Central Plateau (district 96)
Butlers Gorge 10.5 +0.6 15.7 10th 1.4 -0.3 -5.9 24th 90.2 159.3 low 57%
Lake St Clair National Park 10.1 -0.2 15.2 10th 1.1 -0.6 -4.9 24th 106.0 159.8 low 66%
Liawenee 8.7   12.9 17th -0.4   -10.2 22nd 58.0 76.5 average 76%
West Coast (district 97)
Hartz Mountain (Keoghs Pimple) 8.8 +0.1 14.7 10th 3.2 -0.3 -1.2 12th 56.2 69.0 average 81%
Mount Read 6.4 -0.1 10.3 30th 2.1 -0.2 -2.4 22nd 287.8 408.1 low 71%
Scotts Peak Dam 12.1 +0.5 17.4 10th 5.0 -0.6 -0.5 24th 115.4 160.1 average 72%
Strahan Aerodrome 14.8 +0.5 20.7 10th 6.3 -1.1 -0.4 21st 154.8 137.4 average 113%
Strathgordon Village 12.0 +0.5 18.2 10th 5.1 -0.2 -0.4 22nd 177.3 241.1 low 74%
Warra 11.2   17.0 10th 4.1   -2.5 22nd 104.8


King Island (district 98)
King Island Airport 16.1 +0.5 20.5 10th 9.1 -0.2 1.2 22nd 61.0 84.6 low 72%
Flinders Island (district 99)
Flinders Island Airport 16.3 0.0 21.7 4th 7.9 -1.1 -0.2 23rd 55.8 79.4 average 70%
Hogan Island 15.9   20.3 4th 11.8   8.3 12th 72.2


Antarctica and Macquarie Island (district 300)
Macquarie Island 6.5 +0.6 8.0 4th 3.7 +1.2 0.3 13th 71.4 82.9 low 86%

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 June 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

Media
(03) 9669 4057
Enquiries