United States · 1991–2020

Best time to visit
Raritan.

September leads for comfortable weather in Raritan: typically 25.5°C by day, 11.9°C at night, with 97 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortSeptember

Typical high25.5°C

Typical low11.9°C

Rain in September97 mm

Comfort

September

September · August · May

78climate match

Beach

August

August · July · June

74climate match

Outdoors

October

October · May · September

76climate match

The weakest month is January, scoring 5 against September’s 78 — days reach only 0.5°C, 23° 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

50.5° / -9.7°

Feb

53.2° / -7.5°

Mar

1810.3° / -1.8°

Apr

4317.2° / 4°

May

6923° / 10.5°

Jun

6828° / 15.9°

Jul

6129.8° / 17.8°

Aug

7029° / 16.6°

Sep

7825.5° / 11.9°

Oct

5518.5° / 5.3°

Nov

1910.3° / -0.9°

Dec

53.5° / -6.4°

Monthly climate evidence for Raritan — daylight is calculated from latitude, everything else is measured
Month	Day	Night	Rain	Wet days	Daylight	Comfort	Coverage
January	0.5°C	-9.7°C	41 mm	5.6	9 h 33	5	Strong coverage
February	3.2°C	-7.5°C	47 mm	5.5	10 h 35	5	Strong coverage
March	10.3°C	-1.8°C	61 mm	6.1	11 h 49	18	Strong coverage
April	17.2°C	4°C	99 mm	8.9	13 h 14	43	Strong coverage
May	23°C	10.5°C	130 mm	10	14 h 25	69	Strong coverage
June	28°C	15.9°C	125 mm	8.7	15 h 04	68	Strong coverage
July	29.8°C	17.8°C	107 mm	8.1	14 h 49	61	Strong coverage
August	29°C	16.6°C	87 mm	7.1	13 h 47	70	Strong coverage
September	25.5°C	11.9°C	97 mm	6.2	12 h 25	78	Strong coverage
October	18.5°C	5.3°C	79 mm	6.7	11 h 03	55	Strong coverage
November	10.3°C	-0.9°C	64 mm	6.1	9 h 51	19	Strong coverage
December	3.5°C	-6.4°C	52 mm	5.7	9 h 16	5	Strong coverage

What has changed

Raritan runs -0.2°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

+0.1

Feb

-0.2

Mar

+0.7

Apr

-1.0

May

-0.8

Jun

-0.6

Jul

-1.3

Aug

-1.0

Sep

+0.6

Oct

-0.5

Nov

-0.3

Dec

+1.6

September daytime highs, 2011–2025. Last recorded: 28.7°C.

Records at LA HARPE, 1895–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	21.1°C7 Jan 1907	-30.6°C10 Jan 1982	102 mm19 Jan 1907	264 mm1897 · driest 2 mm in 1986	129
February	25.0°C28 Feb 2024	-34.4°C13 Feb 1905	87 mm21 Feb 1997	127 mm1997 · driest 0 mm in 2026	129
March	31.1°C23 Mar 1910	-25.0°C5 Mar 1960	129 mm4 Mar 1985	195 mm1985 · driest 7 mm in 1956	131
April	34.4°C10 Apr 1930	-15.0°C2 Apr 2018	132 mm18 Apr 2013	228 mm2013 · driest 18 mm in 2018	131
May	40.6°C31 May 1934	-3.3°C7 May 1906	112 mm21 May 1899	319 mm1899 · driest 13 mm in 1964	132
June	42.2°C29 Jun 1934	2.8°C12 Jun 1903	260 mm10 Jun 1905	320 mm1905 · driest 12 mm in 1963	132
July	43.3°C15 Jul 1936	5.6°C14 Jul 1975	128 mm25 Jul 1948	370 mm1948 · driest 3 mm in 1916	132
August	45.0°C9 Aug 1934	2.2°C31 Aug 1915	138 mm14 Aug 1898	314 mm1970 · driest 0 mm in 2013	131
September	39.4°C1 Sep 1913	-5.0°C30 Sep 1899	139 mm10 Sep 2014	336 mm1970 · driest 3 mm in 1940	131
October	35.6°C4 Oct 2006	-17.2°C30 Oct 1925	120 mm3 Oct 1986	346 mm1941 · driest 0 mm in 1964	131
November	28.3°C1 Nov 1950	-19.4°C30 Nov 1964	81 mm30 Nov 2006	215 mm1985 · driest 2 mm in 1917	131
December	22.8°C16 Dec 2021	-32.2°C28 Dec 1924	86 mm10 Dec 2003	153 mm1982 · driest 6 mm in 1976	131

Typical days per month at LA HARPE, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)	Snow days
January	0	0	29	1	4
February	0	0	25	1	3
March	1	0	21	2	3
April	4	<1	7	4	2
May	13	3	<1	4	<1
June	24	11	0	4	0
July	29	16	0	3	0
August	28	13	0	3	0
September	18	6	<1	3	<1
October	6	1	6	3	1
November	<1	0	18	2	2
December	0	0	27	2	3

The best month has moved. On the 1961–1990 numbers the strongest month here was May (scoring 81); on 2011–2025 it is September (84). Both are scored the same way, from the same station — only the climate underneath changed.

How often, not how much — every day in LA HARPE’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	<1%	18%	4%	12%	-2.7–5.0°C
February	<1%	18%	5%	15%	-1.0–7.1°C
March	9%	23%	8%	24%	6.4–13.7°C
April	27%	29%	11%	36%	14.6–20.1°C
May	55%	31%	12%	39%	20.5–26.3°C
June	71%	28%	13%	32%	26.0–30.5°C
July	77%	23%	10%	23%	28.4–33.0°C
August	78%	22%	9%	20%	27.4–31.7°C
September	70%	23%	11%	23%	23.7–28.2°C
October	42%	20%	7%	19%	16.8–22.3°C
November	8%	20%	7%	17%	7.3–13.3°C
December	<1%	19%	5%	15%	-0.1–6.5°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.

1897Each stripe is one year’s mean temperature against the 123-year average. Warmest: 1931. Coolest: 2014.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 4907146
NOAA station: USC00114823 · LA HARPE
Station distance: 18 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 30 usable years
Daylight: Calculated from latitude 40.70°, 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 LA HARPE is what differs

Colchester→La Harpe→Blandinsville→Tennessee→Sciota→Burnside→

Or put two places side by side: Raritan vs Colchester

Best time to visitRaritan.