United States · 1991–2020

Best time to visit
Helena.

October leads for comfortable weather in Helena: typically 24.8°C by day, 11.5°C at night, with 86 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortOctober

Typical high24.8°C

Typical low11.5°C

Rain in October86 mm

Comfort

October

October · April · May

81climate match

Beach

September

September · June · August

72climate match

Outdoors

October

October · March · November

71climate match

The weakest month is January, scoring 22 against October’s 81 — days reach only 13°C, 11° below the 24°C the score treats as ideal, and nights drop to 1.4°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

2213° / 1.4°

Feb

2915.3° / 3.3°

Mar

5420.3° / 7.3°

Apr

7224.8° / 10.7°

May

6928.6° / 15.6°

Jun

4732.6° / 20.2°

Jul

3833.6° / 21.8°

Aug

4133.4° / 21.5°

Sep

5930.9° / 18.5°

Oct

8124.8° / 11.5°

Nov

4918.5° / 5.2°

Dec

3014.5° / 3°

Monthly climate evidence for Helena — daylight is calculated from latitude, everything else is measured
Month	Day	Night	Rain	Wet days	Daylight	Comfort	Coverage
January	13°C	1.4°C	122 mm	8.2	10 h 10	22	Good coverage
February	15.3°C	3.3°C	142 mm	9.6	10 h 56	29	Good coverage
March	20.3°C	7.3°C	135 mm	10	11 h 53	54	Good coverage
April	24.8°C	10.7°C	133 mm	8	12 h 58	72	Good coverage
May	28.6°C	15.6°C	109 mm	8.1	13 h 52	69	Good coverage
June	32.6°C	20.2°C	100 mm	9.3	14 h 20	47	Good coverage
July	33.6°C	21.8°C	121 mm	9.7	14 h 09	38	Good coverage
August	33.4°C	21.5°C	112 mm	8.6	13 h 23	41	Good coverage
September	30.9°C	18.5°C	101 mm	6	12 h 20	59	Good coverage
October	24.8°C	11.5°C	86 mm	5.9	11 h 18	81	Good coverage
November	18.5°C	5.2°C	115 mm	6.8	10 h 24	49	Good coverage
December	14.5°C	3°C	118 mm	8.6	9 h 57	30	Good coverage

Records at HELENA, 2003–2021
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	26.1°C13 Jan 2017	-15.6°C30 Jan 2014	71 mm2 Jan 2020	222 mm2020 · driest 56 mm in 2018	18
February	27.8°C21 Feb 2018	-10.0°C5 Feb 2009	78 mm10 Feb 2020	326 mm2020 · driest 71 mm in 2007	18
March	31.7°C25 Mar 2007	-6.7°C6 Mar 2015	137 mm10 Mar 2010	234 mm2010 · driest 27 mm in 2007	18
April	33.3°C18 Apr 2006	-1.7°C8 Apr 2009	94 mm19 Apr 2020	256 mm2014 · driest 28 mm in 2012	18
May	36.1°C31 May 2016	3.9°C10 May 2020	164 mm4 May 2021	230 mm2021 · driest 17 mm in 2011	18
June	41.7°C30 Jun 2012	11.1°C2 Jun 2012	86 mm19 Jun 2021	287 mm2017 · driest 18 mm in 2020	18
July	40.6°C1 Jul 2012	13.3°C30 Jul 2014	121 mm31 Jul 2012	261 mm2021 · driest 28 mm in 2014	18
August	41.7°C15 Aug 2007	11.7°C14 Aug 2004	66 mm12 Aug 2004	230 mm2010 · driest 31 mm in 2016	17
September	38.3°C12 Sep 2019	7.8°C29 Sep 2006	169 mm16 Sep 2004	264 mm2009 · driest 5 mm in 2019	17
October	38.9°C3 Oct 2019	-2.2°C29 Oct 2008	77 mm25 Oct 2019	206 mm2009 · driest 0 mm in 2016	16
November	31.1°C1 Nov 2016	-7.8°C19 Nov 2014	99 mm16 Nov 2014	290 mm2004 · driest 22 mm in 2007	16
December	26.7°C10 Dec 2007	-10.0°C14 Dec 2010	70 mm8 Dec 2018	296 mm2018 · driest 36 mm in 2010	18

Typical days per month at HELENA, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)
January	<1	0	16	4
February	<1	0	11	5
March	8	<1	4	4
April	17	3	<1	4
May	26	15	0	4
June	29	25	0	3
July	31	28	0	4
August	30	28	0	4
September	28	20	0	2
October	17	5	<1	3
November	2	<1	7	3
December	<1	0	12	4

How often, not how much — every day in HELENA’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	9%	27%	13%	30%	10.0–16.2°C
February	19%	34%	18%	44%	11.9–18.7°C
March	41%	33%	14%	42%	17.8–23.0°C
April	65%	26%	13%	28%	23.3–26.7°C
May	74%	26%	12%	29%	26.9–30.4°C
June	70%	32%	13%	42%	30.1–34.3°C
July	68%	32%	13%	36%	31.7–34.9°C
August	71%	29%	12%	32%	31.6–35.3°C
September	81%	20%	8%	18%	28.9–33.5°C
October	70%	19%	8%	20%	23.1–26.3°C
November	33%	23%	11%	23%	16.0–20.7°C
December	12%	28%	13%	33%	12.0–16.3°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.

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 4066811
NOAA station: USC00013781 · HELENA
Station distance: 2.8 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 15 usable years
Daylight: Calculated from latitude 33.30°, 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 HELENA is what differs

Hoover→Alabaster→Pelham→Chelsea→Indian Springs Village→Brantleyville→

Or put two places side by side: Helena vs Hoover

Best time to visitHelena.

October

September

October

The whole year,without the guesswork.

Nearby, measured,and named.

Best time to visit
Helena.

The whole year,
without the guesswork.

Nearby, measured,
and named.