United States · 1991–2020

Best time to visit
Sioux Falls Junction.

August leads for comfortable weather in Sioux Falls Junction: typically 26.1°C by day, 14°C at night, with 89 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortAugust

Typical high26.1°C

Typical low14°C

Rain in August89 mm

Comfort

August

August · June · July

81climate match

Beach

July

July · August · June

65climate match

Outdoors

September

September · May · October

80climate match

The weakest month is January, scoring 5 against August’s 81 — days reach only -5.4°C, 29° 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

5-5.4° / -15.9°

Feb

5-2.5° / -13.8°

Mar

54.2° / -7°

Apr

2612.3° / -0.2°

May

5619.4° / 7.1°

Jun

7824.8° / 13.4°

Jul

7627.4° / 15.6°

Aug

8126.1° / 14°

Sep

7522.3° / 8.8°

Oct

3914.4° / 1.2°

Nov

55.1° / -6.1°

Dec

5-2.6° / -12.5°

Monthly climate evidence for Sioux Falls Junction — daylight is calculated from latitude, everything else is measured
Month	Day	Night	Rain	Wet days	Daylight	Comfort	Coverage
January	-5.4°C	-15.9°C	14 mm	3.3	9 h 14	5	Strong coverage
February	-2.5°C	-13.8°C	19 mm	3.9	10 h 24	5	Strong coverage
March	4.2°C	-7°C	35 mm	4.4	11 h 47	5	Strong coverage
April	12.3°C	-0.2°C	68 mm	6.9	13 h 22	26	Strong coverage
May	19.4°C	7.1°C	104 mm	8.9	14 h 43	56	Strong coverage
June	24.8°C	13.4°C	113 mm	8.7	15 h 28	78	Strong coverage
July	27.4°C	15.6°C	96 mm	6.6	15 h 10	76	Strong coverage
August	26.1°C	14°C	89 mm	6.5	14 h 00	81	Strong coverage
September	22.3°C	8.8°C	78 mm	5.6	12 h 27	75	Strong coverage
October	14.4°C	1.2°C	56 mm	4.9	10 h 55	39	Strong coverage
November	5.1°C	-6.1°C	26 mm	3.5	9 h 34	5	Strong coverage
December	-2.6°C	-12.5°C	22 mm	4	8 h 54	5	Strong coverage

What has changed

Sioux Falls Junction runs -0.5°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

0.0

Feb

-1.3

Mar

+0.3

Apr

-2.2

May

-1.2

Jun

-0.1

Jul

-1.2

Aug

-1.6

Sep

+1.3

Oct

-0.9

Nov

+0.1

Dec

+0.9

August daytime highs, 2011–2025. Last recorded: 26.1°C.

Records at FLANDREAU, 1893–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	17.8°C25 Jan 1981	-40.0°C1 Jan 1974	30 mm30 Jan 2001	45 mm1897 · driest 0 mm in 1974	130
February	21.1°C23 Feb 1958	-38.9°C9 Feb 1899	39 mm29 Feb 2012	59 mm2012 · driest 0 mm in 1923	129
March	30.6°C30 Mar 1943	-31.1°C11 Mar 1948	56 mm14 Mar 2019	100 mm1995 · driest 0 mm in 1915	132
April	34.4°C25 Apr 1962	-18.9°C3 Apr 1975	97 mm23 Apr 2001	199 mm2001 · driest 1 mm in 1926	131
May	41.1°C30 May 1934	-8.9°C11 May 1946	182 mm31 May 2004	363 mm2004 · driest 7 mm in 1940	132
June	40.6°C22 Jun 1988	-1.7°C7 Jun 1901	180 mm16 Jun 1957	255 mm1984 · driest 23 mm in 1978	133
July	44.4°C24 Jul 1940	1.7°C29 Jul 1927	122 mm28 Jul 1942	249 mm1995 · driest 2 mm in 2012	131
August	42.2°C24 Aug 1936	0.0°C28 Aug 1935	116 mm11 Aug 1932	250 mm1902 · driest 9 mm in 2001	132
September	40.0°C17 Sep 1895	-9.4°C29 Sep 1899	120 mm24 Sep 1934	264 mm2010 · driest 3 mm in 2024	131
October	34.4°C2 Oct 1897	-24.4°C29 Oct 1925	71 mm7 Oct 2008	160 mm2007 · driest 0 mm in 1952	130
November	26.1°C4 Nov 1909	-28.9°C30 Nov 1964	40 mm18 Nov 1958	91 mm1922 · driest 0 mm in 1904	130
December	18.3°C2 Dec 1922	-37.2°C29 Dec 1917	33 mm26 Dec 2016	57 mm1909 · driest 0 mm in 1898	130

Typical days per month at FLANDREAU, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)	Snow days
January	0	0	31	<1	5
February	0	0	28	<1	5
March	<1	0	27	<1	3
April	1	<1	16	3	2
May	7	1	2	3	<1
June	16	5	0	4	0
July	24	8	0	3	0
August	20	5	0	3	0
September	11	2	1	3	0
October	2	<1	14	2	<1
November	<1	0	26	<1	2
December	0	0	31	<1	5

The best month has moved. On the 1961–1990 numbers the strongest month here was June (scoring 80); on 2011–2025 it is September (85). Both are scored the same way, from the same station — only the climate underneath changed.

How often, not how much — every day in FLANDREAU’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%	9%	<1%	4%	-9.3–0.1°C
February	<1%	11%	1%	6%	-6.7–2.6°C
March	4%	15%	3%	11%	-0.2–9.5°C
April	19%	23%	7%	24%	9.9–17.3°C
May	44%	27%	9%	33%	18.0–23.9°C
June	63%	29%	12%	32%	23.0–28.5°C
July	77%	22%	8%	19%	25.8–31.5°C
August	77%	22%	8%	19%	24.9–30.5°C
September	59%	20%	8%	18%	20.3–26.0°C
October	29%	15%	5%	12%	12.9–19.0°C
November	3%	11%	3%	6%	1.5–10.0°C
December	0%	10%	1%	5%	-6.0–1.9°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.

1893Each stripe is one year’s mean temperature against the 119-year average. Warmest: 1921. Coolest: 2013.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 5231855
NOAA station: USC00392984 · FLANDREAU
Station distance: 10.3 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 29 usable years
Daylight: Calculated from latitude 43.98°, 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 FLANDREAU is what differs

Flandreau→Elkton→Egan→Trent→Ward→Lone Tree→

Or put two places side by side: Sioux Falls Junction vs Flandreau

Best time to visitSioux Falls Junction.