Monday, 4 October 2021 - Monthly Climate Summary for Western Australia - Product code IDCKGC11R0

Western Australia in September 2021: dry in the south, warm nights in the north

Rainfall was below average for much of the southern half of Western Australia and the Gascoyne District, although the state's south-west saw near average September rainfall. Rainfall in the north of the state was close to average as September was typically dry. Mean maximum and minimum temperatures were close to average for most of WA, although parts of the state's west, south and north recorded warmer than normal days. Nights were much warmer along the Pilbara coast, in contrast to cooler nights in parts of the south.

Dry in the southern half of the state apart from the south-west

• Rainfall was 48% below September the long-term (1961–90) average for Western Australia.
• Many sites in the south-west of the state recorded a handful of days with moderate rainfall during September, and daily totals of up 30–40 mm were recorded in the southern Lower West District on the 16th, including a September daily rainfall record.
• September was typically dry in the north, and a majority of sites registered nil rainfall, with only few sites in the Kimberley and Pilbara recording totals of 0.2–10 mm.

Near average temperatures for most of WA

• Mean maximum and minimum temperatures were close to average for most of the state, although parts of the state's west, south and north recorded warmer than normal days.
• WA mean maximum temperature was 1.17 °C above the long-term (1961–90) average, although it was the coolest September since 2016.
• WA mean minimum temperature matched the long-term (1961–90) average of 12.2 °C.
• Very cold days were observed in the south-west of the state on the 2nd and 3rd with daily maximum temperatures below 15 °C away from the coast, and as low as to 10 °C in the Great Southern District; a number of sites in southern Greater Perth Region recorded their lowest maximum temperature for September on record on the 3rd.
• Very hot days with maximum temperatures of 40 °C or higher were observed at multiple sites in the Kimberley from the middle to the end of September.
• Wyndham Aero recorded a total of 7 days of 40 °C or higher in September, which was its second-highest such number in 22 years of record, behind a count of 10 such days in 2016.
• A number of very cold and frosty nights were observed across a large area of the southern half of WA during September, including 3 consecutive nights between the 3rd and 5th, then between the 12th and 14th; a number of sites in the south-eastern Gascoyne had their lowest September temperature on record on the 3rd.
• Very warm nights were observed in the Kimberley and Pilbara on the 21st and 22nd with overnight temperatures in the mid-to-high twenties; Broome Airport, Port Hedland Airport and several other sites had their highest daily minimum temperature for September on record.
• Derby Airport's minimum temperature of 29.0 °C on the 23rd was not only its September record, but also the state and country's highest September minimum temperature for five years since 28 September 2016.

Extremes Maps Records Summaries Important notes the top

Extremes Maps Records Summaries Important notes the top

Maps
	Observed	Anomaly	Decile rank
Total rainfall
Mean daily maximum temperatures
Mean daily minimum temperatures

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Extremes Maps Records Summaries Important notes the top

Extremes Maps Records Summaries Important notes the top