Monday, 4 September 2023 - Monthly Climate Summary for Greater Perth - Product code IDCKGC11L0

Greater Perth in August 2023

Rainfall

• August was dry across the Greater Perth, with monthly rainfall being 40&ndsh;80% below average.
• Pearce RAAF in the northeast of Perth, recorded the second-lowest August rainfall on record of 22.2 mm, behind the monthly total of 17.6 mm in August 2008.
• Locations in the Perth Hills recorded higher totals in the 70&ndsh;90 mm range, with only Huntly recording over 100 mm (101.5 mm).
• Perth Metro recorded a monthly rainfall total of 75 mm, which was 39% below the August average (123.8 mm).
• A cold front brought widespread moderate falls during mid-August, with 2-day (the 15th and 16th) rainfall totals of 20&ndsh;70 mm.
• Perth Metro recorded a 2-day (to the 16th) total of 60.8 mm, the highest 2-day total in August for 29 years since 67.4 mm in the 5th and 6th of August 1994.

Temperature

• Mean maximum temperatures were 1–2 °C above average, whilst mean minimum temperatures were generally within 0.5 °C of their average.
• Perth Metro recorded a mean maximum temperature of 20.0 °C, the warmest August since 2019 (20.2 °C) or since 2016 (21.6 °C).
• The coldest day was on the 10th with temperatures capping in the low-to-mid 10s. Mandurah had its coldest August day on record.
• The warmest day was on the 31st with temperatures reaching the high 20s to the low 30s. Perth Airport and a number of other sites had their highest August temperature on record.
• Perth Metro recorded a maximum temperature of 29.7 °C on the 31st, which was the second-highest August temperature in 125 years of records, behind the daily maximum temperature of 30.0 °C on 28 August 2019.
• Perth Metro recorded 3 consecutive cold nights with daily minimum temperatures below 5 °C between the 4th and 6th, the last of such a run in August was between 18 and 20 August 2019.

Perth Metro

• Total rainfall for Perth Metro was 75.0 mm, which is 61% of the long-term average of 122.2 mm.
• The mean daily maximum temperature for Perth Metro was 20.4 °C, which is 1.3 °C above the long-term average of 19.1 °C.
• The warmest day was 29.7 °C on the 31st, and the coolest day was on the 10th when the temperature reached 14.5 °C.
• The mean daily minimum temperature for Perth Metro was 8.4 °C, equal to the long-term average.
• The coldest morning was 3.7 °C on the 4th, and the warmest morning was on the 8th when the minimum temperature was 15.4 °C.

Extremes Maps Records Summaries Daily observations Important notes the top

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Extremes in August 2023
Hottest day	30.2 °C at Perth Airport on the 31st
Warmest days on average	20.6 °C at Millendon (Swan Valley) 20.6 °C at Perth Airport
Coolest days on average	17.2 °C at Karnet
Coldest day	11.2 °C at Karnet on the 10th
Coldest night	1.0 °C at Jandakot Aero on the 4th 1.0 °C at Karnet on the 4th
Coolest nights on average	6.7 °C at Karnet
Warmest nights on average	12.8 °C at Rottnest Island
Warmest night	17.6 °C at Rottnest Island on the 8th
Warmest on average overall	15.6 °C at Rottnest Island
Coolest on average overall	11.8 °C at Karnet
Wettest overall	101.5 mm at Huntly
Wettest day	53.0 mm at Araluen on the 16th
Strongest wind gust	128 km/h at Rottnest Island on the 2nd

Extremes Maps Records Summaries Daily observations Important notes the top

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Record highest August temperature
	New record (°C)		Old record		Years of record	Average for August
Perth Airport	30.2	on the 31st	29.9	on the 28th in 2019	80	18.6
Pearce RAAF	29.9	on the 31st	29.6	on the 30th in 1948	64	18.4
Jandakot Aero	29.4	on the 31st	= 29.4	on the 28th in 2019	34	18.7
Rottnest Island	28.3	on the 31st	25.3	on the 15th in 2015	34	17.9




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Record lowest August daily maximum temperature
	New record (°C)		Old record		Years of record	Average for August
Mandurah	12.7	on the 10th	13.3	on the 9th in 2022	22	18.0





Extremes Maps Records Summaries Daily observations Important notes the top

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Summary statistics for August 2023
	Maximum temperatures (°C)				Minimum temperatures (°C)				Rainfall (millimetres)
	Mean for August 2023	Diff from average	Highest for August 2023		Mean for August 2023	Diff from average	Lowest for August 2023		Total for August 2023	Average for August	Rank of August 2023	Fraction of August average
Bickley	17.4	+1.4	26.0	31st	8.1	+0.5	2.7	4th	77.2	174.7	v low	44%
Garden Island HSF	18.3	+0.2	21.1	30th	10.9	-0.3	6.3	4th	34.2	93.3	v low	37%
Jandakot Aero	19.8	+1.1	29.4	31st	7.1	-0.2	1.0	4th	59.6	127.4	v low	47%
Karnet	17.2	+1.2	24.0	25th	6.7	+0.3	1.0	4th	68.4	180.7	v low	38%
Mandurah	18.3	+0.3	26.6	31st	10.8	-0.2	5.5	4th	62.4	93.2	low	67%
Millendon (Swan Valley)	20.6		29.9	31st	7.5		2.4	4th	38.0
Pearce RAAF	20.4	+2.0	29.9	31st	8.0	-0.2	3.6	4th	22.2	105.6	v low	21%
Perth Airport	20.6	+2.0	30.2	31st	8.0	-0.1	2.9	4th	47.2	117.6	v low	40%
Perth Metro	20.4	+1.3	29.7	31st	8.4	0.0	3.7	4th	75.0	122.2	low	61%
Rottnest Island	18.4	+0.5	28.3	31st	12.8	+0.4	9.3	4th	24.8	85.5	lowest	29%
Swanbourne	19.2	+0.4	29.9	31st	10.2	+0.1	4.9	4th	65.0	117.1	v low	56%

Extremes Maps Records Summaries Daily observations Important notes the top

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Daily maximum temperatures for August 2023
	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Bickley	20.7	17.4	12.3	13.3	15.8	20.6	19.1		14.9	11.9	15.6	13.3	16.6	17.0	13.9	12.7	14.9	17.6	18.9	16.1	16.7	14.9	15.9	19.6	23.9	22.5	23.0	20.3	18.3	19.1	26.0
Garden Island HSF	20.8	18.7	13.5	16.1	18.4	18.1	20.9	20.2	17.3	13.8	17.0	17.2	17.2	19.3	19.4	15.3	17.2	17.9	17.2			17.7	17.9	18.5	20.7	20.5	19.6	20.6	19.9	21.1
Jandakot Aero	24.3	20.2	14.5	16.1	19.0	21.6	21.9	20.3	17.9	13.6	18.6	16.7	19.1	19.7	19.3	15.8	17.8	19.3	20.3	18.3	18.1	17.4	18.5	20.9	24.8	23.0	22.1	21.8	21.0	22.6	29.4
Karnet	21.5	18.6	12.5	14.5	17.1	20.9	20.7	17.5	15.5	11.2			16.0	17.3	16.5	13.2	15.4	17.3	18.0	15.5	16.4	14.1	16.2	19.6	24.0	21.0		19.0	16.5	19.5
Mandurah	18.6	17.9	14.0	15.3	17.5	18.8	19.5	18.0	17.1	12.7	17.9	17.6	17.7	19.3	19.1	15.8	16.9	18.6	18.6	17.9	17.4	16.8	17.8	19.1	20.4	20.4	19.7	20.5	19.0	21.8	26.6
Millendon (Swan Valley)	23.9	19.8	15.3	15.9	19.2	22.7	21.5	20.2	18.0	14.4	19.1	17.2	19.4	20.6	18.8	16.1	18.4	20.5	21.6	20.4	19.2	18.5	19.7	21.8	27.3	25.1	25.8	23.3	21.3	22.4	29.9
Pearce RAAF	24.2	19.9	14.9	15.6	18.7	22.5	21.5	20.5	18.3	13.9	18.5	16.0	19.2	20.5	19.6	15.9	17.9	20.1	21.8	20.2	19.0	18.3	19.1	21.4	26.8	25.5	25.3	22.9	21.3	22.5	29.9
Perth Airport	24.8	19.9	15.7	16.5	19.4	23.0	22.4	21.8	18.2	14.7	19.2	17.1	19.7	20.2	18.4	16.8	17.9	20.5	21.4	19.7	19.3	18.6	19.1	22.7	26.7	24.7	24.7	22.5	21.5	22.6	30.2
Perth Metro	25.0	20.2	15.1	16.8	19.3	22.1	22.0	22.1	18.9	14.5	19.2	16.6	19.5	20.4	19.0	16.1	18.3	19.7	20.7	19.9	18.9	17.6	19.3	21.9	25.0	24.3	23.7	22.6	21.2	22.7	29.7
Rottnest Island	20.7	19.6	13.3	14.6	17.5	18.5	20.5	20.6	16.9	14.0	16.4	16.4	17.2	19.8	19.1	15.4	16.8	17.8	17.3	18.8	16.4	16.4	18.1	17.9	20.9	21.3	21.0	20.9	17.7	19.5	28.3
Swanbourne	23.7	19.9	14.0	16.2	18.9	19.1	20.5	20.1	18.0	13.8	17.3	16.8	17.4	20.2	19.3	15.5	17.3	18.9	18.9	19.1	17.9	17.4	18.3	19.3	21.3	21.5	20.7	21.2	20.6	23.0	29.9
Values are the maximum temperature, usually in the 24 hours from 9 am on the day indicated, and typically occurred in the afternoon of that day.
Temperatures coloured according to their difference from the long-term average for the period			-10.0	-9.0	-8.0	-7.0	-6.0	-5.0	-4.0	-3.0	-2.0	-1.0	0.0	+1.0	+2.0	+3.0	+4.0	+5.0	+6.0	+7.0	+8.0	+9.0	+10.0	°C	Grey outline marks highest and lowest for the period

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Daily minimum temperatures for August 2023
	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Bickley	7.7	12.2	3.6	2.7	2.9	6.5	10.0	14.5	6.2	7.0	7.9	7.4	7.9	8.8	9.9	7.6	6.7	8.2	7.8	8.7	8.5	6.9	6.9	7.8	8.9	9.9	11.4	12.2	8.9	6.2	8.6
Garden Island HSF	10.1	14.9	8.7	6.3	7.1	8.7	10.5	16.4	9.9	10.8	10.5	9.5	10.5	9.3	14.5	12.1	10.9	9.6	10.1	10.7		9.0	11.3	11.5	8.3	12.1	11.0	16.8	12.2	10.5	13.5
Jandakot Aero	4.6	13.5	5.8	1.0	1.7	4.3	9.0	15.2	4.7	6.2	9.2	5.2	7.9	5.9	11.1	9.9	7.5	4.5	5.3	5.4	7.4	5.4	7.9	6.3	5.2	7.8	7.9	8.7	9.0	6.6	9.7
Karnet	5.7	12.2	4.5	1.0	2.6	4.9	9.7	14.0	3.3	4.9	7.5			5.4	11.4	7.6	5.5	5.4	5.3	5.2	7.5	3.5	5.9	5.1	6.9	7.3	9.6		8.5	6.0	10.0
Mandurah	11.2	14.9	7.9	5.5	6.9	9.1	11.5	16.2	8.8	10.6	9.5	8.5	9.6	11.1	13.5	10.5	10.3	10.3	9.6	10.2	12.1	8.1	10.5	11.8	10.9	12.0	13.2	15.8	12.2	9.8	12.4
Millendon (Swan Valley)	5.9	13.3	4.1	2.4	3.8	4.3	10.9	14.2	6.1	7.8	9.1	5.6	9.1	6.0	9.1	9.9	5.5	4.5	6.0	5.4	8.0	4.9	4.4	3.8	8.2	7.4	9.3	10.9	10.4	10.1	12.4
Pearce RAAF	7.6	11.9	4.3	3.6	4.2	6.0	10.9	15.7	5.5	7.2	9.7	7.2	10.7	6.4	7.6	9.7	7.1	3.9	5.4	5.9	7.7	5.0	4.3	3.8	11.4	8.6	10.8	11.9	10.7	10.4	14.0
Perth Airport	9.5	13.2	5.3	2.9	5.4	3.4	11.4	14.8	5.5	7.3	10.1	5.0	9.0	6.5	10.1	10.1	6.4	4.5	5.9	6.0	7.3	4.8	6.1	4.5	10.6	8.0	10.8	11.2	11.2	10.0	12.1
Perth Metro	6.6	13.4	6.5	3.7	3.9	4.5	10.4	15.4	7.4	8.2	10.1	5.6	9.9	7.6	10.7	10.0	7.8	5.6	6.0	7.0	9.5	6.6	7.6	6.0	7.2	9.5	10.3	11.6	11.3	8.0	11.0
Rottnest Island	13.9	15.5	9.6	9.3	9.5	11.4	13.8	17.6	12.4	12.6	11.0	11.4	11.3	13.4	14.1	11.8	12.7	13.0	12.7	12.7	12.3	12.2	12.5	13.8	14.0	14.2	15.0	15.3	12.7	11.5	13.7
Swanbourne	9.4	14.7	7.0	4.9	6.0	7.6	11.6	16.3	9.8	9.8	9.4	8.4	10.6	9.6	12.5	10.2	9.4	8.4	8.9	10.2	10.9	9.2	9.7	8.6	10.9	12.0	12.3	14.6	11.4	9.3	12.9
Values are the minimum temperature, usually in the 24 hours to 9 am on the day indicated, and typically occurred that morning.
Temperatures coloured according to their difference from the long-term average for the period			-10.0	-9.0	-8.0	-7.0	-6.0	-5.0	-4.0	-3.0	-2.0	-1.0	0.0	+1.0	+2.0	+3.0	+4.0	+5.0	+6.0	+7.0	+8.0	+9.0	+10.0	°C	Grey outline marks highest and lowest for the period

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Daily rainfall for August 2023
	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Anketell	0.1	0.2	11.4	-	-	-	-	1.0	2.3	0.1	5.1	0.2	-	0.2	11.8	19.2	0.8	0.8	-	-	0.4	-	-	-	-	-	-	-	-	-
Araluen	-	-	11.0	-	-	-	-	-	14.1	-	-	-	-	-	6.0	53.0	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Bickley	-	0.2	9.8	-	-	0.2	-	-		-	7.8	0.2	-	-	17.8	39.0	0.4	0.2	0.2	0.2	1.0	-	-	0.2	-	-	-	-	-	-	-
Bungendore	0.2	-	9.4	0.2	-	0.2	0.2	0.8	13.4	0.2	6.8	0.2	-	0.2	9.2	27.8	0.4	0.2	0.2	0.4	0.6	0.2	-	0.2	-	-	-	-	-	0.2	-
Chidlow	-	-	2.1	-	-	-	-	0.2	13.3	-	8.0	0.2	-	-	1.6	24.8	0.2	-	-	-	-	0.2	-	-	-	-	-	-	-	-	-
Garden Island HSF	-	0.2	11.2	-	-	-	-	0.2	2.0	-	3.4	0.2	-	1.0	4.4	9.6	0.8	0.8	0.2	-			-	0.2	-	-	-	-	-	-	-
Gidgegannup	3.6	-	0.6	0.8	-	-	-	0.2	6.2	7.8	2.2	2.2	1.2	2.4	0.2	11.8	12.6							-	-	-	0.2	-	-	-	-
Huntly	0.8	-	24.0	0.4	-	-	-	-	16.0	0.4	5.8	-	-	-	23.0	28.5	-	-	0.4	-	1.8	-	-	-	-	-	-	0.4	-	-	-
Jandakot Aero	-	-	6.4	-	-	0.2	-	0.8	10.4		8.0	-	-	1.6	10.4	19.8	0.4	-	-	-	1.6	-	-	-	-	-	-	-	-	-	-
Jarrahdale	0.4	-	12.4	-	0.4	-	0.2	1.8	12.0	-	6.2	0.2	-	-	10.8	20.4	0.2	0.4	0.2	-	0.6	0.2	-	-	0.2	0.2	0.2	0.2	-	-	-
Karnet	-	-	13.1	0.1	-	-	-	1.4	17.8	0.5	5.6	→	→	0.3	8.1	17.3	1.2	0.1	1.0	-	1.9	-	-	-	-	-	-	-	-	-	-
Karragullen North	-	-	8.2	-	-	-	-	0.8	11.0	-	8.2	-	-	-	17.0	30.2	0.6
Maida Vale	-	-	4.4	-	-	-	-	0.6	-	4.0	5.4	-	-	-	19.0	23.6	-	-	-	0.6	1.8	-	-	-	-	-	-	-	-	-	-
Mandurah	1.6	-	21.4	-		-	-	0.8	9.0	0.4	4.4	-	-	-	13.0	8.2	1.4	1.4	-	-	0.8	-	-	-	-	-	-	-	-	-	-
Millendon (Swan Valley)	0.2	-	1.2	-	-	0.2	-	0.2	4.6	0.2	6.0	0.2	-	0.4	1.6	21.4	-	-	0.2	-	1.4	0.2	-	-	-	-	-	-	-	-	-
Mount Solus	0.2	0.2	18.6	0.2	0.2	-	-	1.6	14.4	0.2	5.8	0.4	-	0.4	12.4	16.2	0.6	0.6	0.2	0.2	1.6	0.2	-	-	-	0.2	-	-	-	0.2	-
Muchea	-	-	4.6	-	0.2	-	-	0.2	6.0	-	6.4	-	0.2	-	-	9.6	-	-	0.2	-	1.4	-	-	-	-	-	-	-	-	0.2	-
Mundaring	-	-	3.6	-	-	-	-	0.6	9.0	0.2	8.2	-	0.4	-	1.0	29.8	→	0.6	→	→	1.4	-	-	-	-	-	-	-	-	-	-
Pearce RAAF	-	-	3.0	-	-	-	-	-	3.8	-	6.6	-	-	-	0.2	7.0	-	-	-	-	1.2	0.2	-	-	-	-	-	-	-	0.2	-
Perth Airport	-	-	2.4	-	-	-	-	0.2	5.4	-	4.4	0.2	-	-	10.8	22.6	-	-	-	-	1.0	0.2	-	-	-	-	-	-	-	-	-
Perth Metro	-	0.2	3.2	-	-	-	-	0.2	2.0	-	5.4	-	-	0.2	22.8	38.0	0.4	-	-	-	2.2	-	-	-	-	-	-	-	0.4	-	-
Pinjarra South	1.2	-	21.4	-	0.2	-	-	0.8	17.4	1.2	3.6	-	-	-	27.8	10.6	1.4	-	0.2	-	1.6	-	-	-	-	-	-	-	-	-	-
Roleystone	-	-	11.6	-	-	-	-	0.6	8.8	-	9.0	-	-	-	6.6	36.2	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Rottnest Island	0.2	-	8.6	-	-	-	-	-	0.6	-	3.8	-	-	0.4	4.2	2.0	-	4.0	-	-	0.6	0.2	-	0.2	-	-	-	-	-	-	-
Serpentine	0.2	-	12.4	-	-	-	-	0.8	7.4	-	4.4	-	-	-	10.4	11.4	0.4	0.4	0.2	-	0.2	-	-	-	-	-	-	-	-	-	-
Swanbourne	-	-	8.0	-	-	-	-	0.6	3.2	-	7.8	0.2	-	-	17.0	20.0	2.2	0.2	0.2	-	5.4	-	-	-	-	0.2	-	-	-	-	-
Tamala Park (Mindarie)	-	-	8.2	-	-	-	-	0.4	1.5	-	5.4	0.2	-	-	6.2	18.4	0.8	0.2	-	-	1.8	-	-	-	-	-	-	-	-	-	-
Wanneroo	52.4	-	8.0	-	-	-	-	1.4	2.0	-	5.4	-	-	-	7.2	19.4	0.8	-	→	→	1.6	-	-	-	-	-	-	-	0.1	-	-
Werribee	-	0.2	2.2	0.2	-	0.2	-	0.2	7.6	-	6.4	0.2	-	-	0.2	12.4	-	-	0.2	0.2	0.2	-	-	0.2	-	-	-	-	-	-	-
Most values are the precipitation in the 24 hours to 9 am on the day indicated. Days marked with → are part of a longer accumulation, which is shown on the final day. Values over 100 mm have been rounded to the nearest whole millimetre. Days marked with - have a rainfall report of zero; days left blank have no rainfall report (which often indicates no rain fell).
Rainfalls coloured according to the amount	0	1.0	5.0	10.0	15.0	25.0	50.0	100	150	200	300	400	600	millimetres

Extremes Maps Records Summaries Daily observations Important notes the top

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Notes

The Monthly climate summary, usually published in the first week of the following month, lists the main features of the weather in Greater Perth using the most timely and accurate information available on the date of publication; it will generally not be updated.

This summary includes data from observing sites in or near the Greater Perth “Greater Capital City Statistical Area” (GCCSA). The Australian Bureau of Statistics designed the GCCSAs to represent a socio-economic definition of each capital city. This means the greater capital city boundary includes people who regularly socialise, shop or work within the capital city, but live in the small towns and rural areas surrounding the capital city. It does not define the built up edge of the capital city.

This statement has been prepared based on information available at 12 pm on Monday 4 September 2023. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

In some situations, some or all of the rainfall is in the form of hail or snow. In these cases the totals given are for the water equivalent: the depth of liquid water that results from melting any frozen precipitation. There can be significant 'undercatch' of snow in strong winds, meaning the true precipitation can be higher than that reported.

Averages for individual sites 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.

Where temperature area averages are mentioned, they are derived from the ACORN-SAT dataset.

Information about Australian Indigenous seasonal calendars is available at the Indigenous Weather Knowledge website.

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