Wednesday, 1 August 2007 - Monthly Climate Summary for Tasmania - Product code IDCKGC17R0

Tasmania in July 2007:

A cold start, a mild finish, mostly drier than normal

Summary

Cold weather was more prevalent than warm in Tasmania during July, but some mild temperatures near the end of the month prevented a repeat of the exceptionally cold June (but still nothing like the exceptionally warm May). Overall, temperatures were below average during July, except near the East Coast where nights were a little warmer than average. Rain was below average in most of the state, but close to average n the East Coast and even above average in the far southeast.

Details

A cold start, but a mild finish: The 4th marked the start of almost three weeks of below-average maximum (day time) temperatures, with the 17th and 18th especially cold in most areas after a strong cold change. Just as it looked like the month would be a repeat of the very cold June, a week of mild weather started on the 23rd, and on the 25th Scamander reached 21°C and Tarraleah had its highest July temperature since records began there in 1981. The warm spell was not quite enough to counter the extended cold, and taken across the month daytime temperatures were below average by about half a degree, although slightly above average on the northeast coast.

Some frosts, but some mild nights: Minimum (overnight) temperatures were quite variable through the month, with some very cold nights around the 10th, 15th and 21st mixed with some  mild ones around the 8th, 17th and 26th. Although most of the state had a run of cold nights in the middle of the month, the East Coast escaped the worst of it. Overall, nights were about one degree colder than average in the west and north, but about half a degree warmer than average in the east; Bicheno had its  highest July mean daily minimum temperature in 33 years of record.

Another month of below-average rain: Rainfall in the western two-thirds of the state was below average again this month. Although it was not a repeat of the record low rain seen in June a few sites in the Derwent Valley and southern Midlands had their lowest total July rainfall since at least 1979 with monthly totals below 20 mm common in those areas. There were fewer wet days on the west coast than normal, although Strathgordon registered 52 mm and Queenstown 44 mm in the 24 hours to 9 am on the 17th.  A few wet days (around the 5th, 14th and 18th) were enough to give above-average totals for the Tasman Peninsula and southern Bruny Island.

Fewer westerlies: Tasmania's weather is often dominated by westerly winds, but during July these were less common than normal. High pressure systems controlled the weather from the 7th to 15th and again from the 18th to the 23rd, but low pressure systems close to the state were the main influence from the 3rd to the 7th. There was a major cold change on the 17th, with a series of weaker fronts near the end of the month. The lack of westerlies meant less rain than usual in the western half, and periods of easterlies helped keep minimum temperatures above average in the east.

Further information

Ian Barnes-Keoghan
Tasmania and Antarctica Climate Services Centre
Bureau of Meteorology
Phone (03) 6221 2043
Email climate.tas@bom.gov.au

Extremes

Hottest day
Highest temperature
21.2°C at Scamander on the 25th
Warmest days on average
Highest mean daily maximum temperature
14.2°C at Scamander
Coolest days on average
Lowest mean daily maximum temperature
2.8°C at Mount Wellington
Coldest day
Lowest daily maximum temperature
−1.4 °C at Mount Wellington on the 14th
Coldest night
Lowest temperature
−7.6°C at Liawenee on the 21st
Coolest nights on average
Lowest mean daily minimum temperature
−2.0°C at Liawenee
Warmest nights on average
Highest mean daily minimum temperature
8.9°C at Hogan Island
Warmest night
Highest daily minimum temperature
12.8°C at Hogan Island on the 26th
Wettest overall
Highest total rainfall
251.6 mm at Mount Read
Driest overall
Lowest total rainfall
13.8 mm at Tunbridge (Austin-Vale)
Wettest day
Highest daily rainfall
52.0 mm at Strathgordon Village on the 17th
Highest wind gust
137 km/h at Hogan Island on the 3rd

Records

Lowest total July rainfall for at least 20 years
Total rainfall
for July 2007 (mm)
Most recent lower
for July
Years since
lower
Normal for
July
Bushy Park (Bushy Park Estates) 15.6 9.9 in 1957 49 49.4
Bothwell (Cluny) 19.6 17.6 in 1973 33 46.1
Glenorchy (Glenorchy Reservoir) 30.6 25.6 in 1979 28 73.5
Rotherwood 26.0 23.1 in 1979 28 51.4



Record highest July temperature
Highest temperature
in July 2007 (°C)
Previous highest
for July
Years of
record
Normal for
July
Tarraleah Village 15.4 on the 25th 14.5 on the 2nd in 1985 23 8.2



Record highest July mean daily minimum temperature
Mean daily minimum
temperature
for July 2007 (°C)
Previous highest
for July
Years of
record
Normal for
July
Bicheno (Council Depot) 7.3 7.2 in 2001 33 6.0



Summaries

In this table, key sites have been highlighted to make them easier to find. This table is very wide and may not fit if printed.


Summary statistics for July 2007
Maximum temperatures
for July
(°C)
Minimum temperatures
for July
(°C)
Rainfall
for July
(millimetres)
Mean for
July
2007
Diff
from
normal
Highest for
July
2007
Mean for
July
2007
Diff
from
normal
Lowest for
July
2007
Total for
July
2007
Normal
for
July
Rank of
July
2007
Fraction of
July
normal
Northern (district 91)
Bridport 13.1 –0.2 16.0 25th 5.3 –0.1 0.9 18th 79.0 73.4 normal 108%
Burnie 12.8 +0.1 14.7 3rd 6.3 +0.4 2.4 14th 61.4 125.2 low 49%
Cape Grim BAPS 12.0 –0.5 15.4 25th 7.4 –0.9 4.2 21st 140.2 101.2 high 139%
Cressy Research Station 11.7 15.3 3rd 1.3 –4.0 16th 46.0
Devonport Airport 12.4 –0.3 15.1 3rd 3.6 –1.0 –1.1 15th 54.2 97.0 low 56%
Launceston 12.5 –0.1 16.4 25th 2.1 0 –2.2 19th 49.0 76.4 low 64%
Launceston Airport 11.5 15.9 25th 2.1 –2.6 16th 42.6
Launceston Airport Comparison 11.0 +0.1 15.2 25th 2.3 +0.1 –2.1 19th 47.0 77.0 low 61%
Low Head 12.4 –0.4 14.1 26th 6.0 –1.0 2.2 19th 37.6 67.6 very low 56%
Luncheon Hill 10.5 –0.2 15.7 25th 4.3 –0.8 0.2 15th 124.0 183.5 low 68%
Marrawah 12.1 –0.2 15.8 25th 6.2 –0.4 2.7 21st 117.8 138.1 normal 85%
Powranna 11.1 –0.4 15.4 25th 2.2 +0.1 –2.0 19th 46.4 57.2 normal 81%
Scottsdale 11.6 –0.4 15.0 25th 3.6 –0.1 –0.7 1st 77.8 120.3 low 65%
Sheffield School Farm 10.6 –0.3 13.5 25th 2.5 –1.1 –1.2 15th 65.0
Smithton Aerodrome 12.7 –0.4 15.8 24th 2.5 –2.4 –1.7 9th 106.0 112.8 normal 94%
Wynyard Airport 12.6 0 14.9 24th 1.6 –1.9 –2.2 21st 87.0 131.7 low 66%
East Coast (district 92)
Bicheno 14.0 0 18.3 25th 7.3 +1.3 2.4 16th 58.6 53.0 normal 111%
Eddystone Point 13.7 +0.6 16.7 25th 7.6 +0.5 3.6 18th 91.0 76.9 normal 118%
Fingal 11.2 –1.0 18.5 25th 1.2 +0.7 –2.9 16th 50.8 56.0 normal 91%
Friendly Beaches 13.4 –0.5 18.7 25th 5.9 +0.2 1.1 16th 52.2 45.9 normal 114%
Lake Leake 8.0 –0.5 12.9 25th 1.0 +0.8 –3.9 21st 55.0 78.8 normal 70%
Maria Island 12.3 15.4 26th 7.3 4.8 19th 44.8
Orford 12.4 –0.7 17.0 26th 3.8 +0.4 0.2 16th 44.2 59.0 normal 75%
Scamander 14.2 +0.3 21.2 25th 5.6 +1.2 1.5 16th 66.7 55.8 normal 120%
St Helens Aerodrome 13.1 17.7 25th 4.9 0.8 16th 81.6
Swan Island 12.9 14.8 25th 8.0 4.7 18th 96.2
Swansea Post Office 13.4 +0.1 18.4 25th 4.3 +0.7 –0.4 16th 29.0 47.9 normal 61%
Midlands (district 93)
Ross 11.1 –0.2 14.8 25th 1.2 –0.3 –3.2 16th 31.0 40.5 normal 77%
Southeast (district 94)
Bull Bay 11.7 –0.8 16.5 25th 4.9 –1.0 2.0 10th 56.6 55.1 normal 103%
Campania 12.3 16.9 24th 3.1 –0.2 10th 29.2
Cape Bruny 12.0 –0.1 15.9 25th 6.4 –0.3 3.3 10th 109.8 72.9 very high 151%
Cape Bruny Lighthouse 11.6 +0.4 15.9 25th 6.5 +0.3 3.5 10th 136.0 95.6 high 142%
Dover 12.2 –0.2 17.7 25th 2.9 –0.9 –1.3 10th 60.5 86.7 normal 70%
Geeveston 11.9 –0.2 17.5 25th 1.6 –0.7 –2.9 10th 51.6 91.1 low 57%
Grove Comparison 11.7 –0.1 18.5 25th 1.7 –0.3 –2.2 10th 33.6 72.2 low 47%
Grove 11.6 17.9 25th 0.9 –2.7 10th 35.0
Hobart 11.7 0 17.5 25th 4.7 +0.2 1.2 10th 36.0 52.5 normal 69%
Hobart Airport 12.4 0 17.2 24th 4.2 +0.2 1.1 10th 35.2 44.0 normal 80%
Maatsuyker Island Lighthouse 10.8 –0.1 15.9 25th 7.2 +0.6 4.3 18th 101.0 129.4 normal 78%
Melton Mowbray 10.9 –0.5 16.6 26th 1.8 –0.5 –3.0 21st 23.0 29.7 low 77%
Mount Wellington 2.8 +0.5 8.4 23rd –1.0 +0.6 –4.2 16th 109.8 75.9 high 145%
Tasman Island 10.5 15.4 25th 6.6 3.6 14th 142.4
Tunnack Fire Station 8.9 –0.7 14.6 24th 1.2 –0.9 –3.2 29th 37.8 45.3 normal 83%
Derwent Valley (district 95)
Bushy Park 11.7 +0.6 16.2 25th 0.1 –1.4 –4.0 10th 15.6 49.4 very low 32%
Maydena Post Office 10.2 –0.6 16.5 25th 1.0 –1.4 –2.2 21st 61.4 107.2 low 57%
Moogara 8.6 +0.1 14.5 25th 2.1 –0.1 –1.0 21st 25.0 74.3 very low 34%
Ouse Fire Station 11.6 –0.2 19.6 25th 0.0 –1.4 –4.0 10th 18.4 49.2 low 37%
Tarraleah Village 8.2 –0.1 15.4 25th 0.7 +0.3 –3.6 10th 75.5 117.3 low 64%
Central Plateau (district 96)
Lake St Clair National Park 7.2 –0.1 13.1 25th –0.6 –0.6 –5.2 15th 136.1 201.5 low 68%
Liawenee 5.3 12.0 25th –2.0 –7.6 21st 54.6
West Coast (district 97)
Hartz Mountain 6.0 –0.1 12.1 25th 1.4 –0.1 –1.3 18th 77.6
Mount Read 3.4 –0.4 9.6 25th –0.2 –0.4 –3.4 14th 251.6 375.6 low 67%
Scotts Peak Dam 9.4 16.1 25th 3.0 –1.5 10th 150.6
Strahan Aerodrome 11.9 –0.3 18.3 25th 3.7 –1.5 –1.8 15th 166.0 168.4 normal 99%
Strathgordon Village 9.3 +0.3 17.0 25th 2.3 –0.8 –1.2 11th 173.1 269.7 low 64%
Warra 8.3 14.9 25th 2.5 –1.5 10th 88.0
King Island (district 98)
King Island Airport 13.5 +0.4 17.9 25th 6.8 –0.7 0.5 21st 78.0 111.9 low 70%
Flinders Island (district 99)
Flinders Island Airport 13.1 –0.2 18.4 25th 5.8 –0.5 –0.3 15th 65.2 84.5 normal 77%
Hogan Island 12.5 16.5 25th 8.9 5.7 18th 71.6
Macquarie Island (district 300)
Macquarie Island 3.6 –1.3 6.7 17th 0.4 –1.2 –6.4 5th 39.0 71.8 very low 54%

Notes

This statement has been prepared based on information available at 11 am on Wednesday 1 August 2007. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

Normals 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 "normal" 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, normal in decile 4 to 7, high in decile 8 or 9 and very high is in decile 10).
The Fraction of normal shows how much rain has fallen this time as a percentage of the long-term mean.

Further information

Ian Barnes-Keoghan
Tasmania and Antarctica Climate Services Centre
Bureau of Meteorology
Phone (03) 6221 2043
Email climate.tas@bom.gov.au