United States · 1991–2020

Best time to visit
Sioux Falls.

September leads for comfortable weather in Sioux Falls: typically 23.7°C by day, 10.6°C at night, with 69 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortSeptember

Typical high23.7°C

Typical low10.6°C

Rain in September69 mm

Comfort

September

September · August · June

83climate match

Beach

July

July · August · June

77climate match

Outdoors

September

September · May · October

78climate match

The weakest month is January, scoring 5 against September’s 83 — days reach only -3.2°C, 27° below the 24°C the score treats as ideal.

Month by month

The whole year,
without the guesswork.

The bars show the comfort score. Day and night temperatures come from daily observed highs and lows; rain is the historical monthly estimate.

Jan

5-3.2° / -13.5°

Feb

5-0.6° / -11.2°

Mar

56.7° / -4.7°

Apr

3414.4° / 1.4°

May

6320.9° / 8.2°

Jun

7426.6° / 14.4°

Jul

7029° / 17°

Aug

7627.7° / 15.7°

Sep

8323.7° / 10.6°

Oct

4515.6° / 3°

Nov

76.7° / -4.6°

Dec

5-0.8° / -10.8°

Monthly climate evidence for Sioux Falls — daylight is calculated from latitude, everything else is measured
Month	Day	Night	Rain	Wet days	Daylight	Comfort	Coverage
January	-3.2°C	-13.5°C	15 mm	3.2	9 h 17	5	Strong coverage
February	-0.6°C	-11.2°C	21 mm	4.2	10 h 25	5	Strong coverage
March	6.7°C	-4.7°C	41 mm	5.5	11 h 47	5	Strong coverage
April	14.4°C	1.4°C	76 mm	7.8	13 h 21	34	Strong coverage
May	20.9°C	8.2°C	98 mm	9.5	14 h 41	63	Strong coverage
June	26.6°C	14.4°C	107 mm	9.3	15 h 24	74	Strong coverage
July	29°C	17°C	83 mm	6.6	15 h 07	70	Strong coverage
August	27.7°C	15.7°C	85 mm	7	13 h 58	76	Strong coverage
September	23.7°C	10.6°C	69 mm	6.2	12 h 27	83	Strong coverage
October	15.6°C	3°C	60 mm	5.8	10 h 56	45	Strong coverage
November	6.7°C	-4.6°C	31 mm	3.9	9 h 37	7	Strong coverage
December	-0.8°C	-10.8°C	21 mm	4.2	8 h 57	5	Strong coverage

What has changed

Sioux Falls runs +1.0°C
on the 1961–1990 baseline.

Each bar compares the 2011–2025 daytime average for that month against the same month in 1961–1990, measured at the same station. Months where the older record is too thin to compare are left blank.

Jan

+2.0

Feb

+0.4

Mar

+2.2

Apr

-0.4

May

-0.1

Jun

+1.1

Jul

-0.4

Aug

-0.4

Sep

+2.5

Oct

+0.4

Nov

+1.7

Dec

+2.7

September daytime highs, 2011–2025. Last recorded: 26.7°C.

Records at SIOUX FALLS, 1932–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	18.9°C24 Jan 1981	-37.8°C19 Jan 1970	40 mm1 Jan 1960	48 mm2023 · driest 1 mm in 1942	95
February	21.1°C26 Feb 2024	-35.0°C28 Feb 1962	41 mm19 Feb 1952	103 mm1962 · driest 0 mm in 1937	95
March	31.7°C21 Mar 2026	-30.6°C11 Mar 1948	83 mm31 Mar 2007	126 mm2007 · driest 4 mm in 1967	95
April	34.4°C25 Apr 1962	-15.6°C3 Apr 1936	95 mm22 Apr 2001	177 mm2001 · driest 4 mm in 1969	95
May	40.0°C30 May 1934	-8.3°C4 May 1967	107 mm29 May 2004	229 mm1936 · driest 3 mm in 1934	95
June	43.3°C21 Jun 1988	0.6°C13 Jun 1969	108 mm16 Jun 1957	348 mm2014 · driest 19 mm in 2012	95
July	43.3°C17 Jul 1936	3.3°C30 Jul 1971	85 mm1 Jul 1992	217 mm2010 · driest 6 mm in 2012	95
August	42.8°C24 Aug 1936	1.1°C20 Aug 1950	138 mm7 Aug 2022	237 mm1932 · driest 14 mm in 1970	94
September	40.0°C6 Sep 1976	-5.6°C30 Sep 1974	102 mm11 Sep 1966	236 mm1986 · driest 1 mm in 2024	93
October	35.0°C1 Oct 2023	-12.8°C19 Oct 1972	115 mm9 Oct 1973	160 mm1998 · driest 0 mm in 1933	94
November	27.8°C6 Nov 2020	-27.2°C30 Nov 1964	49 mm23 Nov 2001	121 mm2001 · driest 0 mm in 2023	94
December	17.2°C2 Dec 1998	-33.3°C23 Dec 1990	36 mm3 Dec 1955	75 mm1945 · driest 0 mm in 1944	94

Typical days per month at SIOUX FALLS, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)	Snow days
January	0	0	31	<1	7
February	0	0	27	<1	7
March	<1	0	25	1	5
April	2	<1	13	3	2
May	9	2	1	3	<1
June	20	8	0	3	0
July	27	13	0	3	0
August	25	8	0	3	0
September	13	4	<1	2	0
October	3	<1	10	2	<1
November	<1	0	24	<1	4
December	0	0	30	<1	7

The best month has moved. On the 1961–1990 numbers the strongest month here was June (scoring 80); on 2011–2025 it is September (87). Both are scored the same way, from the same station — only the climate underneath changed.

How often, not how much — every day in SIOUX FALLS’s record sorted by what it was actually like, rather than averaged
Month	Warm & dry days	Wet days	Washouts	Week with 3+ wet days	Daytime mean has ranged
January	0%	11%	<1%	5%	-8.7–1.5°C
February	<1%	14%	2%	9%	-5.3–3.8°C
March	5%	19%	4%	17%	1.2–10.7°C
April	22%	24%	7%	26%	11.2–17.9°C
May	49%	28%	9%	33%	19.0–24.7°C
June	67%	30%	11%	35%	24.4–29.2°C
July	77%	23%	8%	22%	27.4–32.1°C
August	76%	22%	8%	19%	26.0–31.0°C
September	62%	20%	7%	20%	20.8–26.3°C
October	31%	15%	4%	11%	13.6–19.2°C
November	3%	12%	3%	7%	2.8–10.0°C
December	0%	12%	2%	8%	-4.8–2.8°C

A warm and dry day reaches 20°C with under 1 mm of rain; a wet day gets 1 mm or more; a washout gets 10 mm or more. The week column is the share of seven-day stretches in that month, across the station’s whole daily record, that contained three or more wet days — the odds a week-long trip is rained on repeatedly, counted rather than modelled. The last column is the 10th to 90th percentile of that month’s daytime average across individual years: a narrow band means the average is what you will get, a wide one means the average is a midpoint between years that felt quite different.

1932Each stripe is one year’s mean temperature against the 93-year average. Warmest: 2024. Coolest: 1950.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 5231851
NOAA station: USW00014944 · SIOUX FALLS
Station distance: 4.9 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 30 usable years
Daylight: Calculated from latitude 43.54°, mid-month, sunrise to sunset including refraction. Not a station measurement.
Important limit: Historical climate is not a forecast. Nearby stations can miss mountains, coasts, and local microclimates.

These places read the same station, so their numbers are identical — distance from SIOUX FALLS is what differs

Brandon→Tea→Hartford→Crooks→Shindler→Meadow View Addition→

Or put two places side by side: Sioux Falls vs Brandon

Best time to visitSioux Falls.

September

July

September

The whole year,without the guesswork.

Sioux Falls runs +1.0°Con the 1961–1990 baseline.

Nearby, measured,and named.

Best time to visit
Sioux Falls.

The whole year,
without the guesswork.

Sioux Falls runs +1.0°C
on the 1961–1990 baseline.

Nearby, measured,
and named.