United States · 1991–2020

Best time to visit
Bar Nunn.

September leads for comfortable weather in Bar Nunn: typically 24.6°C by day, 7°C at night, with 29 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortSeptember

Typical high24.6°C

Typical low7°C

Rain in September29 mm

Comfort

September

September · June · August

82climate match

Beach

August

August · July · June

72climate match

Outdoors

September

September · May · June

79climate match

The weakest month is January, scoring 5 against September’s 82 — days reach only 3.6°C, 20° below the 24°C the score treats as ideal, and nights drop to -8.1°C.

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

53.6° / -8.1°

Feb

53.4° / -8.6°

Mar

179.5° / -3.9°

Apr

3513.9° / -0.4°

May

5819.2° / 4.7°

Jun

8026.8° / 10.2°

Jul

7131.8° / 14.1°

Aug

7530.1° / 12.8°

Sep

8224.6° / 7°

Oct

4615.8° / 1°

Nov

189.1° / -3.5°

Dec

53.1° / -7.9°

Monthly climate evidence for Bar Nunn — daylight is calculated from latitude, everything else is measured
Month	Day	Night	Rain	Wet days	Daylight	Comfort	Coverage
January	3.6°C	-8.1°C	12 mm	3.1	9 h 20	5	Good coverage
February	3.4°C	-8.6°C	15 mm	3.5	10 h 27	5	Good coverage
March	9.5°C	-3.9°C	26 mm	3.9	11 h 47	17	Good coverage
April	13.9°C	-0.4°C	41 mm	6.4	13 h 20	35	Good coverage
May	19.2°C	4.7°C	63 mm	7.7	14 h 37	58	Good coverage
June	26.8°C	10.2°C	30 mm	5	15 h 20	80	Good coverage
July	31.8°C	14.1°C	31 mm	5	15 h 03	71	Good coverage
August	30.1°C	12.8°C	23 mm	4.3	13 h 56	75	Good coverage
September	24.6°C	7°C	29 mm	4.4	12 h 26	82	Good coverage
October	15.8°C	1°C	31 mm	4.9	10 h 58	46	Good coverage
November	9.1°C	-3.5°C	11 mm	2.9	9 h 40	18	Good coverage
December	3.1°C	-7.9°C	19 mm	4	9 h 02	5	Good coverage

Records at CASPER WWTP, 2001–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	16.7°C21 Jan 2005	-34.4°C12 Jan 2024	18 mm22 Jan 2018	44 mm2023 · driest 0 mm in 2010	26
February	17.2°C7 Feb 2026	-32.2°C18 Feb 2006	19 mm29 Feb 2004	26 mm2012 · driest 4 mm in 2007	26
March	27.8°C26 Mar 2026	-27.8°C10 Mar 2022	38 mm30 Mar 2016	63 mm2021 · driest 2 mm in 2026	26
April	29.4°C25 Apr 2012	-20.0°C3 Apr 2020	34 mm25 Apr 2016	80 mm2016 · driest 14 mm in 2018	26
May	33.9°C14 May 2026	-7.8°C1 May 2019	66 mm6 May 2007	164 mm2019 · driest 0 mm in 2013	26
June	38.3°C16 Jun 2021	-1.1°C1 Jun 2018	54 mm16 Jun 2023	137 mm2023 · driest 3 mm in 2006	26
July	40.0°C14 Jul 2005	1.7°C26 Jul 2015	47 mm26 Jul 2005	69 mm2018 · driest 4 mm in 2016	26
August	38.3°C14 Aug 2003	1.7°C23 Aug 2016	37 mm12 Aug 2022	80 mm2022 · driest 6 mm in 2002	25
September	36.1°C5 Sep 2022	-10.0°C13 Sep 2014	30 mm21 Sep 2009	52 mm2025 · driest 3 mm in 2015	25
October	30.0°C2 Oct 2011	-22.8°C30 Oct 2019	39 mm4 Oct 2013	67 mm2021 · driest 3 mm in 2016	24
November	22.2°C3 Nov 2008	-29.4°C14 Nov 2014	11 mm27 Nov 2004	28 mm2004 · driest 1 mm in 2025	25
December	18.9°C3 Dec 2021	-36.7°C22 Dec 2022	22 mm15 Dec 2015	48 mm2016 · driest 1 mm in 2023	25

Typical days per month at CASPER WWTP, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)	Snow days
January	0	0	27	<1	4
February	0	0	25	<1	5
March	0	0	24	<1	3
April	1	0	17	1	3
May	7	2	4	2	<1
June	19	9	<1	1	0
July	29	23	0	<1	0
August	26	18	0	<1	0
September	16	6	1	1	<1
October	3	<1	12	1	1
November	0	0	22	<1	2
December	0	0	26	<1	4

How often, not how much — every day in CASPER WWTP’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%	3%	0.1–5.6°C
February	0%	12%	<1%	4%	0.6–6.9°C
March	6%	12%	2%	7%	6.0–12.5°C
April	21%	20%	3%	19%	11.3–16.2°C
May	44%	25%	7%	26%	15.8–21.6°C
June	76%	18%	4%	16%	23.7–29.9°C
July	85%	15%	3%	10%	30.3–33.5°C
August	84%	15%	2%	7%	28.2–32.0°C
September	72%	15%	3%	14%	22.7–26.8°C
October	35%	15%	4%	10%	13.2–19.2°C
November	4%	9%	<1%	2%	6.0–12.1°C
December	0%	12%	<1%	6%	0.9–6.6°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.

2001Each stripe is one year’s mean temperature against the 22-year average. Warmest: 2024. Coolest: 2019.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 5817809
NOAA station: USC00481569 · CASPER WWTP
Station distance: 7.1 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 19 usable years
Daylight: Calculated from latitude 42.91°, 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 CASPER WWTP is what differs

Casper→Mills→Evansville→Hartrandt→Meadow Acres→Brookhurst→

Or put two places side by side: Bar Nunn vs Casper

Best time to visitBar Nunn.

September

August

September

The whole year,without the guesswork.

Nearby, measured,and named.

Best time to visit
Bar Nunn.

The whole year,
without the guesswork.

Nearby, measured,
and named.