United States · 1991–2020

Best time to visit
Washington Boro.

September leads for comfortable weather in Washington Boro: typically 25.2°C by day, 15.7°C at night, with 127 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortSeptember

Typical high25.2°C

Typical low15.7°C

Rain in September127 mm

Comfort

September

September · May · June

77climate match

Beach

August

August · July · June

79climate match

Outdoors

October

October · May · April

74climate match

The weakest month is January, scoring 5 against September’s 77 — days reach only 3.5°C, 20° 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

53.5° / -4°

Feb

55° / -3.3°

Mar

129.9° / 0.7°

Apr

4917.1° / 6.5°

May

7322.3° / 12°

Jun

6627.6° / 17.5°

Jul

5130.3° / 20.3°

Aug

6229.2° / 19.4°

Sep

7725.2° / 15.7°

Oct

5518.3° / 9.5°

Nov

2811.7° / 3.4°

Dec

56.4° / -0.7°

Monthly climate evidence for Washington Boro — daylight is calculated from latitude, everything else is measured
Month	Day	Night	Rain	Wet days	Daylight	Comfort	Coverage
January	3.5°C	-4°C	92 mm	9.3	9 h 37	5	Good coverage
February	5°C	-3.3°C	70 mm	7.4	10 h 37	5	Good coverage
March	9.9°C	0.7°C	107 mm	9.1	11 h 49	12	Good coverage
April	17.1°C	6.5°C	93 mm	8.8	13 h 12	49	Good coverage
May	22.3°C	12°C	99 mm	10.3	14 h 22	73	Good coverage
June	27.6°C	17.5°C	119 mm	9.8	15 h	66	Good coverage
July	30.3°C	20.3°C	122 mm	9.8	14 h 45	51	Good coverage
August	29.2°C	19.4°C	94 mm	8	13 h 45	62	Good coverage
September	25.2°C	15.7°C	127 mm	7.8	12 h 24	77	Good coverage
October	18.3°C	9.5°C	119 mm	7.8	11 h 04	55	Good coverage
November	11.7°C	3.4°C	81 mm	7.1	9 h 55	28	Good coverage
December	6.4°C	-0.7°C	98 mm	8.3	9 h 21	5	Good coverage

Records at SAFE HARBOR DAM, 1995–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	19.4°C7 Jan 2007	-16.1°C8 Jan 2014	85 mm31 Jan 2013	173 mm1996 · driest 27 mm in 2008	26
February	23.9°C22 Feb 2018	-17.2°C6 Feb 1996	46 mm17 Feb 2003	139 mm2014 · driest 12 mm in 2002	26
March	26.1°C11 Mar 2026	-13.3°C1 Mar 2014	89 mm22 Mar 2019	161 mm2019 · driest 22 mm in 2006	27
April	33.9°C28 Apr 2009	-2.8°C5 Apr 1995	62 mm23 Apr 2006	181 mm2011 · driest 32 mm in 1995	27
May	36.7°C20 May 1996	-1.1°C9 May 2020	64 mm15 May 2010	237 mm2025 · driest 29 mm in 2023	27
June	36.7°C25 Jun 2025	7.8°C1 Jun 1996	116 mm28 Jun 2006	357 mm2006 · driest 48 mm in 2024	27
July	40.6°C23 Jul 2011	13.3°C13 Jul 1996	85 mm30 Jul 2007	258 mm2025 · driest 44 mm in 2002	27
August	37.8°C3 Aug 2002	11.1°C31 Aug 2025	118 mm28 Aug 2011	245 mm2011 · driest 31 mm in 2014	26
September	35.6°C1 Sep 2010	6.1°C22 Sep 2020	137 mm2 Sep 2021	307 mm2018 · driest 7 mm in 2007	26
October	32.2°C10 Oct 2007	-1.1°C30 Oct 2007	141 mm1 Oct 2010	285 mm2005 · driest 2 mm in 2024	26
November	26.7°C1 Nov 2024	-7.8°C23 Nov 2018	89 mm17 Nov 2006	215 mm2018 · driest 27 mm in 2015	26
December	22.8°C2 Dec 2006	-15.0°C24 Dec 2022	80 mm18 Dec 2023	198 mm2023 · driest 24 mm in 2021	26

Typical days per month at SAFE HARBOR DAM, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)	Snow days
January	0	0	23	3	3
February	0	0	22	2	3
March	<1	0	14	3	2
April	3	<1	2	3	<1
May	10	2	0	4	0
June	24	9	0	4	0
July	30	18	0	4	0
August	29	14	0	3	0
September	16	4	0	3	0
October	3	<1	<1	4	<1
November	0	0	6	3	<1
December	0	0	19	4	2

How often, not how much — every day in SAFE HARBOR DAM’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%	29%	10%	30%	0.8–6.6°C
February	<1%	28%	9%	28%	2.1–8.4°C
March	5%	28%	11%	30%	7.2–13.1°C
April	25%	30%	11%	37%	14.5–19.2°C
May	50%	34%	12%	43%	20.5–24.9°C
June	68%	31%	12%	36%	26.1–29.1°C
July	68%	32%	12%	38%	28.6–32.0°C
August	73%	27%	10%	28%	27.5–30.4°C
September	71%	26%	12%	25%	23.6–27.1°C
October	30%	25%	11%	23%	16.8–20.3°C
November	4%	24%	8%	24%	9.4–14.0°C
December	<1%	28%	10%	30%	4.1–9.4°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.

2002Each stripe is one year’s mean temperature against the 24-year average. Warmest: 2012. Coolest: 2014.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 4562043
NOAA station: USC00367732 · SAFE HARBOR DAM
Station distance: 10 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 20 usable years
Daylight: Calculated from latitude 39.99°, 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 SAFE HARBOR DAM is what differs

Millersville→Airville→Susquehanna Trails→Conestoga→East Prospect→Felton→

Or put two places side by side: Washington Boro vs Millersville

Best time to visitWashington Boro.