United States · 1991–2020

Best time to visit
Sterling.

September leads for comfortable weather in Sterling: typically 24°C by day, 11.5°C at night, with 101 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortSeptember

Typical high24°C

Typical low11.5°C

Rain in September101 mm

Comfort

September

September · June · August

81climate match

Beach

July

July · August · June

73climate match

Outdoors

May

May · September · October

75climate match

The weakest month is January, scoring 5 against September’s 81 — days reach only 1.6°C, 22° 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

51.6° / -8.3°

Feb

53.4° / -7.4°

Mar

57.9° / -3°

Apr

3415.1° / 2.7°

May

6421.1° / 8.6°

Jun

7525.6° / 13.9°

Jul

6828.9° / 17.1°

Aug

7328° / 16°

Sep

8124° / 11.5°

Oct

4216.8° / 4.9°

Nov

1710.5° / -0.3°

Dec

54.6° / -5.1°

Monthly climate evidence for Sterling — daylight is calculated from latitude, everything else is measured
Month	Day	Night	Rain	Wet days	Daylight	Comfort	Coverage
January	1.6°C	-8.3°C	67 mm	7.7	9 h 23	5	Good coverage
February	3.4°C	-7.4°C	76 mm	7.6	10 h 29	5	Good coverage
March	7.9°C	-3°C	97 mm	8.3	11 h 48	5	Good coverage
April	15.1°C	2.7°C	96 mm	9.4	13 h 18	34	Good coverage
May	21.1°C	8.6°C	95 mm	10.1	14 h 34	64	Good coverage
June	25.6°C	13.9°C	117 mm	10.3	15 h 16	75	Good coverage
July	28.9°C	17.1°C	89 mm	8.5	15 h	68	Good coverage
August	28°C	16°C	89 mm	8.2	13 h 54	73	Good coverage
September	24°C	11.5°C	101 mm	7.2	12 h 26	81	Good coverage
October	16.8°C	4.9°C	114 mm	8.5	10 h 59	42	Good coverage
November	10.5°C	-0.3°C	83 mm	7.9	9 h 43	17	Good coverage
December	4.6°C	-5.1°C	87 mm	8.6	9 h 05	5	Good coverage

Records at FITCHBURG MUNI AP, 1997–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	21.1°C12 Jan 2020	-25.0°C31 Jan 2026	41 mm24 Jan 2019	142 mm2024 · driest 19 mm in 2004	29
February	26.7°C21 Feb 2018	-26.0°C24 Feb 2015	71 mm13 Feb 2008	225 mm2008 · driest 24 mm in 2024	29
March	31.7°C31 Mar 1998	-24.4°C7 Mar 2003	79 mm14 Mar 2010	279 mm2010 · driest 14 mm in 2006	29
April	34.4°C14 Apr 2023	-9.3°C6 Apr 2016	68 mm1 Apr 2004	195 mm2004 · driest 21 mm in 1999	29
May	36.7°C28 May 2016	-1.7°C7 May 2001	57 mm31 May 1998	201 mm2006 · driest 22 mm in 2015	29
June	37.8°C24 Jun 2025	2.2°C1 Jun 2009	82 mm6 Jun 2000	256 mm2006 · driest 23 mm in 2021	29
July	39.4°C22 Jul 2011	8.3°C31 Jul 2001	64 mm29 Jul 2026	300 mm2023 · driest 27 mm in 2011	29
August	37.8°C2 Aug 2006	7.2°C24 Aug 2003	81 mm28 Aug 2011	265 mm2018 · driest 23 mm in 2025	28
September	35.6°C8 Sep 2015	-2.2°C29 Sep 2000	130 mm11 Sep 2023	310 mm2023 · driest 1 mm in 2016	28
October	30.6°C5 Oct 2007	-9.3°C31 Oct 2020	95 mm8 Oct 2005	344 mm2005 · driest 15 mm in 2001	29
November	26.7°C6 Nov 2024	-13.8°C22 Nov 2018	55 mm14 Nov 2009	230 mm2018 · driest 12 mm in 2012	29
December	23.3°C7 Dec 1998	-21.6°C23 Dec 2008	56 mm23 Dec 2022	163 mm2022 · driest 7 mm in 2019	29

Typical days per month at FITCHBURG MUNI AP, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)
January	0	0	28	3
February	0	0	26	3
March	<1	<1	23	4
April	2	<1	9	3
May	9	3	<1	3
June	18	7	0	4
July	27	13	0	3
August	26	10	0	3
September	13	3	<1	3
October	2	<1	6	3
November	<1	0	18	3
December	0	0	26	3

How often, not how much — every day in FITCHBURG MUNI AP’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%	25%	9%	26%	-1.0–4.6°C
February	<1%	26%	9%	29%	0.8–6.5°C
March	4%	28%	11%	35%	5.0–11.1°C
April	19%	31%	11%	39%	12.9–17.0°C
May	46%	32%	11%	38%	19.1–23.3°C
June	63%	34%	12%	44%	24.4–28.0°C
July	71%	29%	10%	33%	26.1–30.7°C
August	74%	26%	10%	25%	26.6–29.5°C
September	66%	24%	10%	24%	22.5–25.1°C
October	24%	28%	11%	31%	15.2–19.0°C
November	5%	26%	8%	29%	8.1–13.2°C
December	<1%	28%	11%	34%	2.0–7.8°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.

1998Each stripe is one year’s mean temperature against the 28-year average. Warmest: 2012. Coolest: 2003.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 4952005
NOAA station: USW00004780 · FITCHBURG MUNI AP
Station distance: 13.1 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 22 usable years
Daylight: Calculated from latitude 42.44°, 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 FITCHBURG MUNI AP is what differs

Leominster→Fitchburg→Lancaster→Clinton→Boylston→Ayer→

Or put two places side by side: Sterling vs Leominster

Best time to visitSterling.

September

July

May

The whole year,without the guesswork.

Nearby, measured,and named.

Best time to visit
Sterling.

The whole year,
without the guesswork.

Nearby, measured,
and named.