Australia in October 2011

In Brief

Warmer than normal overnight temperatures generally recorded for Australia in October 2011, particularly so across the southern mainland. Maximum temperatures were close to normal.

Rainfall was substantially higher than usual across much of the western and northern regions of Australia.


Temperatures

Maximum temperatures averaged across Australia for October were close to the long-term average, recording a national anomaly of +0.09 °C. Notable state values included Tasmania, which observed its 5th warmest maxima for October, and an area-average 0.97 °C warmer than usual. No other states were in the top or bottom ten historical records, however, daytime temperatures averaged across Western Australia were the coolest since 2001 (10 years).

October maximum temperatures were generally close to the long-term average, and didnít deviate beyond 2 °C above or below normal, with only a few patches in the warmest or coolest 10% of years. Maximum temperature anomalies cooler than −1 °C were recorded along the eastern NSW-Queensland border, western SA and areas in WA, namely, the southern Kimberley, an area surrounding Meekatharra and the coastline between Exmouth and Karratha. Temperature anomalies warmer than +1 °C were recorded in southwest WA, an area along the NSW-Victorian border, parts of western Queensland, extending into northern SA, and scattered parts of the tropical north of Australia. The remainder of the country was within 1 °C of normal.

Overnight minimum temperatures for Australia as a whole were 0.59 °C above normal, and ranked as equal 16th warmest on record. Southwest WA (south of a line connecting Jurien Bay and Bremer Bay) was very warm, observing its 3rd warmest October overnight temperatures, and southern Australia as a whole (south of a 26 °S line) measured its 10th warmest October. State wise, minimum temperatures in Victoria were particularly warm, with its area-average of +1.03 °C ranking as the 4th warmest on record, the highest value since 1975. SA recorded its equal 8th warmest minima.

Minimum temperatures more than 1 °C warmer than usual occurred across southern WA, the southern NT as well as the eastern Top End, most of SA, the western coast of Victoria and the Cape York Peninsula in Queensland. Some of these areas, mostly in southern WA and western SA, exceeded 2 °C warmer than usual. Areas surrounding Perth and Albany in WA, as well as much of the Nullarbor, recorded their highest October minima on record. Higher than usual rainfall during October most likely contributed to the warmer than usual minimum temperatures across the southwestern region. Minima cooler than 1 °C below normal were confined to a couple of pockets, namely small areas on the Kimberley coast, and an area near Roma in Queensland.


Areal average temperatures
  Maximum Temperature Minimum Temperature
Rank
(out of 62)
Anomaly*
(°C)
Comment Rank
(out of 62)
Anomaly*
(°C)
Comment
Australia 30 +0.09 46.5 +0.59
Queensland 35 +0.45 37 +0.36
New South Wales 31 +0.12 35 +0.26
Victoria 46 +0.83 59 +1.03 4th highest; highest since 1975
Tasmania 58 +0.97 22 −0.31
South Australia 35 +0.24 54.5 +1.40
Western Australia 20 −0.39 Lowest since 2001 51 +0.81
Northern Territory 34.5 +0.20 32 +0.04

*Anomaly is the departure from the long-term (1961-1990) average.


Temperature maps
MeanAnomalyDeciles
Mean
daily
maximum
temperatures
Map of mean daily maximum temperature Map of mean daily maximum temperature anomalies Map of mean daily maximum temperature deciles
Mean
daily
minimum
temperatures
Map of mean daily minimum temperature Map of mean daily minimum temperature anomalies Map of mean daily minimum temperature deciles

Rainfall

Rainfall averaged over Australia was 52% above normal (17th wettest of 112 years of record). Generally, the northern tropics and the western half of the continent were wetter than usual, with the remainder of the country close to normal. WA recorded its 3rd wettest October.

Areas of above average rainfall were recorded across the western half of Australia, as well as most of SA apart from the southeast, the Cape York Peninsula in Queensland, along the NSW-Queensland border, and coastal NSW from Sydney northwards. The Gippsland region of Victoria also received above average falls.

Areas of highest of record falls for October were observed in parts of inland southern WA (see map below), as well as a small area in the southern NT, and a region surrounding Cairns in Queensland. This region in Queensland is typically one of the wettest areas in Australia, and Bellenden Ker Top Station measured its wettest October on record, with 1494 mm, making it Australiaís wettest October monthly value on record. The previous record of 1313 mm was set last year, also at Bellenden Ker Top Station. Its highest daily rainfall of 440 mm, recorded on the 19th, was the second highest daily October value (record is 551.2 mm at Pacific Heights, Queensland, set 8 October 1914).

Below average falls were recorded in the southeast NT stretching into western Queensland, an area of southern NSW extending into northern Victoria, as well as an area surrounding Mount Gambier in SA, and parts of Tasmania. Only a few very isolated areas were in the lowest decile.


Areal average rainfall
Rank
(out of 112)
Average
(mm)
Departure
from mean*
Comment
Australia 96 35.4 +52%
Queensland 76 30.3 +18%
New South Wales 51 37.2 −16%
Victoria 43 51.6 −19%
Tasmania 35 103.8 −16%
South Australia 90 28.3 +54%
Western Australia 110 38.7 +203% 3rd highest; highest since 1975
Northern Territory 95 34.2 +81%
Murray-Darling Basin 54 35.3 −12%

*The mean is calculated for the 1961-1990 reference period.


Rainfall maps
TotalsPercentagesDeciles
Total
rainfall
Map of total rainfall Map of percentage of normal rain Map of rainfall deciles


Australian weather extremes in October 2011
Hottest day 44.0 °C at Wyndham Aero (WA) on the 12th
Coldest day −0.9 °C at Mount Buller (VIC) on the 1st
Coldest night −7.8 °C at Thredbo AWS (NSW) on the 3rd
Warmest night 28.0 °C at Wyndham (WA) on the 24th
Wettest day 440.0 mm at Bellenden Ker Top Station (QLD) on the 19th


Notes

The Monthly Climate Summary is prepared to list the main features of the weather in Australia using the most timely and accurate information available on the date of publication; it will generally not be updated.

This statement has been prepared based on information available at 2pm EST on Tuesday 1 November 2011. Some checks have been made on the data, but it is possible that results will change as new information becomes available, especially for rainfall where much more data becomes available as returns are received from volunteers.

Long-term averages in this statement and associated tables are for the period 1961 to 1990 unless otherwise specified.

In the tables, fractional ranks denote tied values.

A new area-averaging method was adopted for rainfall in May 2009. Current and historical totals for Tasmania are substantially higher than under the old scheme, but differences for other states, and nationally, are negligible. The rankings and departures from mean shown here use the new method.


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