Tasmania in September 2012: Spring arrives

A cold burst at the end, several warm days but a few cold nights, rain and showers, and destructive winds: in many ways September 2012 was a classic Tasmanian spring month. Overall it was warmer than usual, with rain above average in most areas.

  • Warm days and nights overall
  • Very windy between the 6th and 9th
  • Warm on the 27th
  • Devonport's coldest September night in 17 years

A few wet bursts

September rainfall was above average across most of Tasmania, with some areas well above average. At most sites it was wetter than in 2011 but there have been wetter Septembers sometime in the last few years.

The wettest September days were from the 5th to 9th, the 21st to 23rd, and the 28th to 30th. A cold front produced daily rainfall totals of up to 50 mm in the north, west and central areas on the 5th, though totals were generally less than 10 mm in the southeast. Similar daily rainfall totals were observed in the west and in central areas through to the 8th as several cold fronts crossed Tasmania. Mount Read recorded 50.8 mm in the 24 hours to 9am on the 7th, the wettest day of the month.

A trough of low pressure crossed Tasmania overnight on the 20th and into the 21st as a low pressure system moved through Bass Strait. Rainfall totals of up to 40 mm were recorded in the north and west in the 24 hours to 9am on the 21st, while falls of around 10 to 20 mm were observed elsewhere. Heavier rain developed in the southeast on the 21st as the low moved into the Tasman Sea, with totals of up to 40 mm recorded in the 24 hours to 9am on the 22nd. Tea Tree, just north of Hobart, recorded its wettest September day on record with 36.8 mm to 9 am on the 22nd. A cold front followed on the 23rd producing falls of up to 20 mm in most areas, and up to 40 mm in the west. A cold outbreak at the end of the month brought rain across the state, with some thunderstorms and hail, and snow down to around 400 m.

Mount Read was the wettest location, recording at least 431 mm (the actual total is probably higher as some snow was not properly captured), followed by Strathgordon Village with 372 mm. Maria Island (Point Lesueur) was the driest location with only 28 mm.

Warm days overall

There were many cool days throughout September, but there were also some very warm ones; overall days were warmer than usual.

The 27th was the warmest day of the month, with maximum temperatures generally 3 to 8 degrees above average, and as much as 10 degrees above average in eastern districts where temperatures peaked in the mid twenties. Friendly Beaches recorded the highest temperature with 26.6 °C, the warmest day of the month.

The 4th and 5th were warm days for so early in Spring, with maximum temperatures up to 7 degrees above average due to warm northerly winds ahead of a cold front, reaching into the low twenties along the east coast and into the high teens elsewhere. Days were also warm around the 12th and the 22nd.

The coldest days were around the 7th, 17th, 24th and 29th. Cold southwesterly winds and rain kept temperatures below 15 °C on the 7th, and below 5 °C in central areas. On Mount Wellington the temperature only reached a maximum of -1.8 °C on the 29th, the coldest day of September.

Maximum temperatures were up to one degree warmer than average overall, but were not as warm as in September last year. The warmest days were at Friendly Beaches where the maximum temperature averaged at 16.7 °C for the month, whilst the coolest days on average were at Mount Wellington with 5.9 °C.

Some very cold nights, some very mild nights

There were several very cold nights in September, but some very warm ones too; overall nights were warmer than usual.

Nights were especially cold over the first few days of the month. Temperatures dropped below zero in the northwest and approached -5 °C in central areas. Liawenee recorded the coldest nights of the month during this period, with -7.0 °C on the 1st and -6.2 °C on the 4th. In Devonport the temperature dropped to -0.3 °C on the morning of the 1st, its coldest September temperature in 17 years (since -2.0 °C was recorded on 8 September 1995). It was also quite cold on the 15th when sub-zero temperatures were recorded in central and northern parts, and around the 24th to 25th. There were some reports of frost on the morning of the 26th.

There were also several mild nights throughout September, but the warmest tended to be in the second half of the month. A moist and warm northerly flow kept minimum temperatures 2 to 6 degrees above average between the 19th and 23rd, and on the 27th and 28th. Flinders Island Airport recorded the warmest night of the month on the 27th, when the temperature only fell to a minimum of 14.0 °C, its warmest September night in 10 years (since a minimum of 15.7 °C was recorded on 16 September 2002).

Overall, minimum temperatures were up to one degree warmer than average across Tasmania. The coolest nights on average were -0.5 °C at Mount Wellington, whilst the warmest nights on average were at Swan Island with 9.3 °C.

Strong winds, hail and snow

Strong and gusty winds affected Tasmania between the 6th and 9th as a series of vigorous cold fronts crossed the state. Wind gusts in excess of 100 km/h were recorded in coastal areas on these days, with associated power outages affecting several thousand premises. Conditions were wet and windy across much of the state as a cold front crossed Tasmania on the 7th, with thunderstorms and hail in the south and west and snow down to 300 m. Wind gusts reached 137 km/h at Scotts Peak and 106 km/h at Wynyard, where an uprooted tree landed on a car. The strongest wind gust of 159 km/h was recorded at Hogan Island.

On the 8th, an intense low pressure system to the southwest of New Zealand and a high over the western Great Australian Bight directed a strong west to southwest flow over Tasmania, with snow down to 400 m. Wind gusts exceeded 100 km/h in the northwest, southeast and central areas, peaking at 130 km/h on Mount Wellington and 107 km/h in Hobart and Liawenee. The strong winds caused roof damage in many areas north of the central plateau and around Hobart and Geeveston. More trees were felled in Wynyard, and in Hobart a large branch was brought down in Salamanca Place. Windy conditions continued across most of Tasmania on the 9th (Mount Wellington recorded a maximum wind gust of 156 km/h and Bruny Island a wind gust of 113 km/h), though no damage was reported.

The 29th saw another cold outbreak bring showers, thunderstorms, hail and gusty winds to much of the state. Showers fell as snow to around 400 m, and wind gusts over 100 km/h were reported from several exposed sites.

A warm start to Spring in Hobart

Despite a cold end to September, both maximum and minimum temperatures were warmer than average in Hobart for the month overall. The mean maximum temperature of 15.9 °C was 0.8 °C above the long-term average, whilst the mean minimum temperature of 7.3 °C, was 0.9 °C above average. The warmest day was on the 27th, when the temperature reached a balmy 25.0 °C. Other warm days up around 20 °C were on the 4th, 5th, and 12th. There was a lack of especially cold days: the temperature stayed below 12 °C on only 3 days (the 10th, 18th and 29th), compared to an average of 5 days for September.

Hobart had many mild nights: the temperature remained above 10 °C on 8 mornings, more than double the September average of 3. The warmest minimum temperature was on the morning of the 23rd, when the temperature only fell to 12.2 °C. There were a few cold nights, the temperature dropping below 5 °C on 8 mornings which is close to the average of 9. The coldest morning was on the 1st, when the temperature fell to 2.8 °C.

Hobart's September rainfall total of 68 mm was almost 15 mm above average. The wettest days were on the 7th and 21st, when daily totals of close to 15 mm were recorded in the 24 hours to 9 am on the 8th and 22nd respectively.

Further information

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Extremes in September 2012
Hottest day 26.6 °C at Friendly Beaches on the 27th
Warmest days on average 16.7 °C at Friendly Beaches
Coolest days on average 5.9 °C at Mount Wellington
Coldest day -1.8 °C at Mount Wellington on the 29th
Coldest night -7.0 °C at Liawenee on the 1st
Coolest nights on average -0.5 °C at Mount Wellington
Warmest nights on average9.3 °C at Swan Island
Warmest night 14.0 °C at Flinders Island Airport on the 27th
Warmest on average overall 12.3 °C at Bicheno (Council Depot) and Eddystone Point
Coolest on average overall 2.8 °C at Mount Wellington
Wettest overall 431.4 mm at Mount Read *
372.0 mm at Strathgordon Village
Driest overall28.0 mm at Maria Island (Point Lesueur)
Wettest day 50.8 mm at Mount Read on the 7th
Highest wind gust 159 km/h at Hogan Island on the 7th
156 km/h at Mount Wellington on the 9th

* The true total at Mount Read is probably higher, as it is likely some snow was lost.


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 September daily rainfall
Highest daily rainfall
in September 2012 (mm)
Previous wettest
for September
Years of
record
Tea Tree (The Point) 36.8 on the 22nd 35.2 on the 12th in 2005 27



Summary statistics for September 2012
Maximum temperatures
for September
(°C)
Minimum temperatures
for September
(°C)
Rainfall
for September
(millimetres)
Mean for
September
2012
Diff
from
average
Highest for
September
2012
Mean for
September
2012
Diff
from
average
Lowest for
September
2012
Total for
September
2012
Average
for
September
Rank of
September
2012
Fraction of
September
average
Northern (district 91)
Bridport (Sea View Villas) 14.7 0.0 19.1 27th 6.8 0.0 1.8 14th 73.6 74.3 average 99%
Burnie (Round Hill) 15.1 +0.8 18.3 27th 7.5 +0.7 3.3 1st 124.0 88.0 high 141%
Cape Grim 13.2   16.3 4th 8.5   4.9 29th 92.0
Cape Grim BAPS (Comparison) 13.6 +0.2 16.3 27th 8.4 -0.2 4.7 29th 95.2 77.3 average 123%
Cressy Research Station 15.0 +0.3 19.0 27th 4.4 +0.5 -2.4 15th 88.4 63.6 high 139%
Devonport Airport 14.6 +0.5 17.8 22nd 6.4 +0.4 -0.3 1st 88.6 74.7 average 119%
Launceston (Ti Tree Bend) 16.2 +0.7 20.4 22nd 5.6 +0.4 0.5 15th 71.2 66.1 average 108%
Launceston Airport 15.4   20.4 27th 4.1   -1.4 4th 62.6
Low Head 13.8 -0.2 17.0 22nd 8.6 +0.1 4.6 1st 53.0 65.0 low 82%
Luncheon Hill (Forestry) 12.8 +0.5 19.3 22nd 5.3 -0.1 0.5 1st 206.0 177.2 high 116%
Marrawah 13.8 +0.1 16.7 27th 7.6 +0.2 3.7 1st 111.4 105.3 average 106%
Scottsdale (West Minstone Road) 14.4 +0.2 18.8 27th 5.1 +0.4 -0.9 2nd 90.6 98.2 average 92%
Sheffield School Farm 13.6 +0.5 19.4 27th 4.6 -0.1 -0.4 1st 152.4 125.4 average 122%
Smithton Aerodrome 14.6 -0.2 19.0 27th 5.8 -0.4 -0.3 1st 99.8 103.8 average 96%
Wynyard Airport 14.8 +0.4 20.5 27th 4.9 0.0 -0.9 1st 127.0 96.1 high 132%
East Coast (district 92)
Bicheno (Council Depot) 16.3 +0.2 24.1 27th 8.2 +0.8 3.0 15th 54.7 44.4 high 123%
Eddystone Point 16.1 +1.2 22.6 27th 8.4 +0.4 4.3 2nd 52.0 63.2 average 82%
Fingal (Legge Street) 15.7 +0.4 22.5 27th 4.0 +0.8 -3.4 15th 56.4 49.4 average 114%
Friendly Beaches 16.7 0.0 26.6 27th 7.4 -0.1 0.8 2nd 55.0 38.5 high 143%
Lake Leake (Elizabeth River) 11.7 +0.4 18.9 27th 2.4 +0.4 -4.5 2nd 84.2 70.9 high 119%
Maria Island (Point Lesueur) 14.9   20.0 27th 8.3   4.6 8th 28.0
Orford (Aubin Court) 15.7 0.0 22.9 27th 6.6 +1.1 0.8 15th 52.3 51.6 average 101%
Scamander 16.6 +0.3 23.5 27th 6.4 -0.2 1.5 25th 72.6 54.7 high 133%
St Helens Aerodrome 16.2 +0.3 22.3 27th 6.7 +0.2 1.4 2nd 84.4 52.4 high 161%
Swan Island 14.7 +0.2 18.7 27th 9.3 +0.3 5.3 1st
Swansea (Francis Street) 16.4   24.9 27th 6.1   -0.2 2nd 40.5
Midlands (district 93)
Ross (The Boulevards) 14.7 +0.3 19.3 27th 4.4 +0.8 -3.1 15th 83.8 54.6 high 153%
Southeast (district 94)
Bull Bay (Lauriston)     24.4 27th 6.9 +0.2 3.7 8th 60.4 55.6 average 109%
Campania (Kincora) 15.7 -0.4 24.1 27th 6.1 +0.9 0.6 2nd 59.4 49.8 average 119%
Cape Bruny (Cape Bruny) 14.7 +0.4 22.9 27th 7.3 -0.1 4.2 30th 102.2 72.1 high 142%
Cape Bruny Lighthouse 14.3 +1.1 21.7 27th 7.3 +0.3 3.1 25th 108.3 81.5 high 133%
Dover 15.0 +0.4 23.2 27th 5.0 +0.1 1.8 2nd 95.6 84.1 high 114%
Dunalley (Stroud Point) 15.5   25.4 27th 7.7   2.6 2nd 47.6
Geeveston (Cemetery Road) 14.7 0.0 22.6 27th 4.8 +0.3 -1.9 2nd 113.0 94.0 high 120%
Grove (Research Station) 15.2   24.3 27th 4.4   -1.3 2nd 82.0
Hobart (Ellerslie Road) 15.9 +0.8 25.0 27th 7.3 +0.9 2.8 1st 68.0 53.5 high 127%
Hobart Airport 15.8 +0.5 24.1 27th 6.9 +0.9 1.9 2nd 39.8 42.2 average 94%
Maatsuyker Island Lighthouse 12.7 +0.5 19.4 5th 7.1 +0.3 2.9 24th 99.0 109.6 average 90%
Melton Mowbray (North Stockman) 14.4 -0.1 22.4 27th 4.5 +0.2 -0.6 2nd 58.4 53.7 average 109%
Mount Wellington 5.9 +1.6 14.4 27th -0.5 +0.8 -5.4 1st
Tasman Island 12.7 +0.2 22.2 27th 7.0 +0.3 2.8 8th 96.0 88.1 average 109%
Tunnack Fire Station 12.3 -0.1 18.3 27th 3.3 0.0 -1.9 15th 74.6 66.2 average 113%
Derwent Valley (district 95)
Bushy Park (Bushy Park Estates) 15.9 +0.5 24.7 27th 4.6 +0.7 -2.4 2nd 69.4 54.4 high 128%
Maydena Post Office 13.5 -0.1 22.0 27th 4.1 +0.7 -1.4 1st 163.7 143.4 average 114%
Ouse Fire Station 15.3 -0.3 23.0 27th 4.0 +0.2 -3.1 1st 72.6 73.3 average 99%
Central Plateau (district 96)
Butlers Gorge 10.4 +0.3 16.9 27th 1.1 +0.1 -5.3 2nd 247.8 170.5 high 145%
Lake St Clair National Park 10.7 +0.7 17.5 27th 1.0 +0.1 -4.1 4th 285.5 220.2 high 130%
Liawenee 9.3 +0.6 15.3 27th -0.4 +0.2 -7.0 1st 122.2 124.3 average 98%
West Coast (district 97)
Cape Sorell 14.2 +1.1 18.1 4th 8.1 +0.2 4.1 1st 114.0 123.1 average 93%
Hartz Mountain (Keoghs Pimple) 8.5 0.0 16.3 27th 1.8 0.0 -1.9 30th
Low Rocky Point 14.2   19.9 4th 7.4   3.4 1st
Mount Read 5.7 +0.4 12.1 22nd 0.3 0.0 -5.0 1st 431.4*
Scotts Peak Dam 12.9 +0.8 19.8 22nd 4.4 +0.1 0.7 1st 281.8 226.7 high 124%
Strahan Aerodrome 14.7 +0.4 20.3 27th 6.6 +0.4 0.5 1st 186.8 156.3 high 120%
Strathgordon Village 12.1 +0.6 18.8 27th 4.5 +0.1 0.5 1st 372.0 283.9 high 131%
Warra 11.6   20.1 27th 3.2   -0.6 1st 255.2
King Island (district 98)
King Island Airport 14.7 +0.1 19.5 4th 8.1 -0.2 4.6 3rd 71.0 87.5 average 81%
Flinders Island (district 99)
Flinders Island Airport 15.8 +0.7 25.3 27th 8.1 +0.6 1.0 2nd
Antarctica and Macquarie Island (district 300)
Macquarie Island 5.6 +0.2 7.9 24th 2.0 +0.5 -3.1 19th 73.4 74.7 average 98%

* The true total at Mount Read is probably higher, as it is likely some snow was lost.


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 8 am on Monday 1 October 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