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Pasco, Washington climate

BSk Cold semi-arid

Pasco has a seasonal mild-temperate climate (Cold semi-arid, Köppen BSk). The hottest month is July with an average daily high near 33°C, while the coldest is January averaging around −2°C at night. Precipitation totals about 200 mm a year and is strongly seasonal — January alone averages 29 mm while August barely receives 4 mm.

☀️ Summers

Hot

Highs near 33°C in July.

About 47 days a year above 32 °C

❄️ Winters

Cold

Lows near −2°C in January.

About 75 freezing nights a year

🌧️ Rain

Very dry

About 200 mm of rain a year.

Wettest in January

⛅ Sky & trend

Partly cloudy

A roughly even mix of sun and cloud.

+0.5 °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

Clear vs cloudy days

Share of days each month that are clear, partly cloudy or cloudy · 1991–2020 · hover a month for the day counts

Pasco climate normals (1991–2020)

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Avg high (°C)	5	9	15	19	24	28	33	32	27	19	11	5
Avg temp (°C)	2	4	8	12	17	21	25	24	19	13	6	2
Avg low (°C)	−2	−1	2	6	10	14	17	16	12	6	2	−1
Precipitation (mm)	29	20	17	15	21	15	5	4	7	17	22	27

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Avg high (°C)	5	9	15	19	24	28
Avg temp (°C)	2	4	8	12	17	21
Avg low (°C)	−2	−1	2	6	10	14
Precipitation (mm)	29	20	17	15	21	15

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Avg high (°C)	33	32	27	19	11	5
Avg temp (°C)	25	24	19	13	6	2
Avg low (°C)	17	16	12	6	2	−1
Precipitation (mm)	5	4	7	17	22	27

How often — frequency of weather events

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Days with measurable rain (days)	11	8	8	7	6	4	2	2	3	6	9	10
Days with high ≥ 32°C (days)	—	—	—	—	2	5	19	17	4	—	—	—
Days with low ≤ 0°C (days)	18	16	8	1	—	—	—	—	—	2	11	19
Days with snowfall ≥ 2.5 cm (days)	0.6	0.4	0.1	—	—	—	—	—	—	—	0.1	0.5

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Days with measurable rain (days)	11	8	8	7	6	4
Days with high ≥ 32°C (days)	—	—	—	—	2	5
Days with low ≤ 0°C (days)	18	16	8	1	—	—
Days with snowfall ≥ 2.5 cm (days)	0.6	0.4	0.1	—	—	—

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Days with measurable rain (days)	2	2	3	6	9	10
Days with high ≥ 32°C (days)	19	17	4	—	—	—
Days with low ≤ 0°C (days)	—	—	—	2	11	19
Days with snowfall ≥ 2.5 cm (days)	—	—	—	—	0.1	0.5

Sky & atmosphere

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Cloud cover (%)	75	68	67	62	58	50	30	31	40	56	70	74
Clear days (≤ 30% cloud)	2	4	4	5	7	9	19	18	14	8	3	2
Partly cloudy days (30–70%)	9	8	10	11	10	11	8	9	9	10	10	9
Cloudy days (≥ 70%)	21	16	17	14	13	9	4	4	7	12	17	20
Relative humidity (%)	81	73	64	58	53	49	43	42	47	60	73	79
Wind speed (m/s)	2.5	2.5	2.7	2.7	2.7	2.8	2.7	2.5	2.3	2.4	2.5	2.5

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Cloud cover (%)	75	68	67	62	58	50
Clear days (≤ 30% cloud)	2	4	4	5	7	9
Partly cloudy days (30–70%)	9	8	10	11	10	11
Cloudy days (≥ 70%)	21	16	17	14	13	9
Relative humidity (%)	81	73	64	58	53	49
Wind speed (m/s)	2.5	2.5	2.7	2.7	2.7	2.8

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Cloud cover (%)	30	31	40	56	70	74
Clear days (≤ 30% cloud)	19	18	14	8	3	2
Partly cloudy days (30–70%)	8	9	9	10	10	9
Cloudy days (≥ 70%)	4	4	7	12	17	20
Relative humidity (%)	43	42	47	60	73	79
Wind speed (m/s)	2.7	2.5	2.3	2.4	2.5	2.5

Methodology & sources

Temperature & precipitation — the official 1991–2020 climate normals from NOAA's U.S. Climate Normals, measured at Kennewick (NOAA GHCN station USC00454154), about 3 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 →