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Ottumwa, Iowa climate

Dfa Hot-summer humid continental

Ottumwa has a strongly seasonal cool-temperate climate (Hot-summer humid continental, Köppen Dfa). The hottest month is July with an average daily high near 86°F, while the coldest is January averaging around 14°F at night. Precipitation totals about 37 inches a year and is strongly seasonal — June alone averages 5.4 inches while January barely receives 1.01 inches. Light snow accumulates each winter (24 inches of snow per year on average).

☀️ Summers

Warm

Highs near 86°F in July.

About 19 days a year above 90 °F

❄️ Winters

Very cold

Lows near 14°F in January.

About 131 freezing nights a year

🌧️ Rain & snow

Moderate rainfall

About 37 in of rain a year, plus 24 in of snow.

Snow falls through the winter months

⛅ Sky & trend

Partly cloudy

A roughly even mix of sun and cloud.

−0.0 °F vs 50 years ago

Temperature & precipitation

Daily high–low temperature range with the monthly average, plus monthly precipitation split into rain and snow · 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

Ottumwa climate normals (1991–2020)

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Avg high (°F)	32	37	50	63	73	82	86	84	77	64	50	37
Avg temp (°F)	23	27	40	51	62	72	75	73	65	53	40	28
Avg low (°F)	14	18	29	39	51	61	65	62	53	42	30	20
Precipitation (in)	1.0	1.4	2.2	3.8	5.0	5.4	3.9	4.4	3.5	2.8	2.1	1.4
Snowfall (in)	7.1	5.8	3.0	1.4	—	—	—	—	—	0.5	1.6	4.2

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Avg high (°F)	32	37	50	63	73	82
Avg temp (°F)	23	27	40	51	62	72
Avg low (°F)	14	18	29	39	51	61
Precipitation (in)	1.0	1.4	2.2	3.8	5.0	5.4
Snowfall (in)	7.1	5.8	3.0	1.4	—	—

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Avg high (°F)	86	84	77	64	50	37
Avg temp (°F)	75	73	65	53	40	28
Avg low (°F)	65	62	53	42	30	20
Precipitation (in)	3.9	4.4	3.5	2.8	2.1	1.4
Snowfall (in)	—	—	—	0.5	1.6	4.2

How often — frequency of weather events

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Days with measurable rain (days)	7	7	10	12	13	11	9	9	8	8	8	7
Days with high ≥ 90°F (days)	—	—	—	—	0.6	4	8	5	2	0.1	—	—
Days with low ≤ 32°F (days)	29	25	20	6	0.4	—	—	—	0.2	5	18	27
Days with snowfall ≥ 1 in (days)	1	0.6	0.4	0.1	—	0.0	—	—	—	0.0	0.3	0.5

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Days with measurable rain (days)	7	7	10	12	13	11
Days with high ≥ 90°F (days)	—	—	—	—	0.6	4
Days with low ≤ 32°F (days)	29	25	20	6	0.4	—
Days with snowfall ≥ 1 in (days)	1	0.6	0.4	0.1	—	0.0

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Days with measurable rain (days)	9	9	8	8	8	7
Days with high ≥ 90°F (days)	8	5	2	0.1	—	—
Days with low ≤ 32°F (days)	—	—	0.2	5	18	27
Days with snowfall ≥ 1 in (days)	—	—	—	0.0	0.3	0.5

Sky & atmosphere

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Cloud cover (%)	65	65	65	65	65	58	49	50	47	57	62	65
Clear days (≤ 30% cloud)	5	4	5	6	5	7	10	10	12	8	6	5
Partly cloudy days (30–70%)	11	10	11	9	10	11	13	12	10	9	10	11
Cloudy days (≥ 70%)	15	14	16	16	16	13	9	9	9	14	14	15
Relative humidity (%)	85	81	76	73	75	76	73	71	70	73	79	85
Wind speed (mph)	8.3	8.4	8.5	8.3	6.9	5.9	5.2	5.0	5.8	6.8	7.4	7.4

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Cloud cover (%)	65	65	65	65	65	58
Clear days (≤ 30% cloud)	5	4	5	6	5	7
Partly cloudy days (30–70%)	11	10	11	9	10	11
Cloudy days (≥ 70%)	15	14	16	16	16	13
Relative humidity (%)	85	81	76	73	75	76
Wind speed (mph)	8.3	8.4	8.5	8.3	6.9	5.9

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Cloud cover (%)	49	50	47	57	62	65
Clear days (≤ 30% cloud)	10	10	12	8	6	5
Partly cloudy days (30–70%)	13	12	10	9	10	11
Cloudy days (≥ 70%)	9	9	9	14	14	15
Relative humidity (%)	73	71	70	73	79	85
Wind speed (mph)	5.2	5.0	5.8	6.8	7.4	7.4

Methodology & sources

Temperature & precipitation — the official 1991–2020 climate normals from NOAA's U.S. Climate Normals, measured at Ottumwa Ind AP (NOAA GHCN station USW00014950), about 9 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 →