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Phoenix, Arizona climate

BWh Hot desert

Phoenix has a seasonal tropical climate (Hot desert, Köppen BWh). The hottest month is July with an average daily high near 41°C, while the coldest is December averaging around 7°C at night. Precipitation totals about 183 mm a year and is strongly seasonal — August alone averages 24 mm while June barely receives 1 mm.

☀️ Summers

Extreme heat

Highs near 41°C in July.

About 173 days a year above 32 °C

❄️ Winters

Cool

Lows near 7°C in December.

🌧️ Rain

Very dry

About 183 mm of rain a year.

Wettest in August

⛅ Sky & trend

Fairly sunny

More sun than cloud through the year.

+0.9 °C vs 50 years ago

Temperature & precipitation

Daily high–low temperature range with the monthly average, plus monthly precipitation · 1991–2020 normals · hover a month for the exact figures

Hours of sunshine per day

Estimated sunny hours each month — daylight length × clear-sky fraction · 1991–2020 monthly cloud cover (NASA POWER)

Phoenix climate normals (1991–2020)

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Avg high (°C)	20	22	26	30	35	40	41	41	38	32	25	19
Avg temp (°C)	14	16	19	23	28	33	35	35	32	25	18	13
Avg low (°C)	8	9	13	16	21	26	29	29	26	19	12	7
Precipitation (mm)	22	22	21	6	3	1	23	24	14	14	14	19

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Avg high (°C)	20	22	26	30	35	40
Avg temp (°C)	14	16	19	23	28	33
Avg low (°C)	8	9	13	16	21	26
Precipitation (mm)	22	22	21	6	3	1

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Avg high (°C)	41	41	38	32	25	19
Avg temp (°C)	35	35	32	25	18	13
Avg low (°C)	29	29	26	19	12	7
Precipitation (mm)	23	24	14	14	14	19

How often — frequency of weather events

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Days with measurable rain (days)	4	4	3	2	1	0.5	4	5	3	2	2	4
Days with high ≥ 32°C (days)	—	0.0	2	10	24	29	31	31	28	17	1	—
Days with low ≤ 0°C (days)	0.4	0.1	—	—	—	—	—	—	—	—	—	0.1

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Days with measurable rain (days)	4	4	3	2	1	0.5
Days with high ≥ 32°C (days)	—	0.0	2	10	24	29
Days with low ≤ 0°C (days)	0.4	0.1	—	—	—	—

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Days with measurable rain (days)	4	5	3	2	2	4
Days with high ≥ 32°C (days)	31	31	28	17	1	—
Days with low ≤ 0°C (days)	—	—	—	—	—	0.1

Sky & atmosphere

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Cloud cover (%)	42	44	38	31	26	20	43	42	28	27	33	42
Relative humidity (%)	47	45	40	31	23	16	29	35	32	30	35	45
Wind speed (m/s)	1.9	1.9	2.0	2.2	2.2	2.2	2.0	1.8	1.9	2.0	2.0	1.9

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Cloud cover (%)	42	44	38	31	26	20
Relative humidity (%)	47	45	40	31	23	16
Wind speed (m/s)	1.9	1.9	2.0	2.2	2.2	2.2

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Cloud cover (%)	43	42	28	27	33	42
Relative humidity (%)	29	35	32	30	35	45
Wind speed (m/s)	2.0	1.8	1.9	2.0	2.0	1.9

30-year delta table (1991–2020 minus 1981–2010, °F)

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Δ Max temp	+0.4	+0.1	+1.2	+0.3	-0.3	+0.3	+0.4	+0.7	+0.6	+0.7	+1.0	+0.2
Δ Avg temp	+0.4	+0.2	+1.1	+0.5	-0.1	+0.6	+0.7	+0.8	+0.8	+0.7	+1.0	+0.4
Δ Min temp	+0.4	+0.3	+1.0	+0.6	+0.1	+0.9	+1.0	+0.9	+1.2	+0.8	+1.0	+0.5

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Δ Max temp	+0.4	+0.1	+1.2	+0.3	-0.3	+0.3
Δ Avg temp	+0.4	+0.2	+1.1	+0.5	-0.1	+0.6
Δ Min temp	+0.4	+0.3	+1.0	+0.6	+0.1	+0.9

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Δ Max temp	+0.4	+0.7	+0.6	+0.7	+1.0	+0.2
Δ Avg temp	+0.7	+0.8	+0.8	+0.7	+1.0	+0.4
Δ Min temp	+1.0	+0.9	+1.2	+0.8	+1.0	+0.5

Methodology & sources

Temperature & precipitation — the official 1991–2020 climate normals from NOAA's U.S. Climate Normals, measured at Phoenix AP (NOAA GHCN station USW00023183), about 7 km from the city centre.

Cloud, humidity, wind & sunshine — modelled estimates from NASA POWER, NASA's satellite-and-reanalysis climatology. This is the standard global source for atmospheric variables, which are not measured at most weather stations.

How we build these numbers →