United States · 1991–2020

Best time to visit
Riverhead.

September leads for comfortable weather in Riverhead: typically 24.6°C by day, 15.5°C at night, with 103 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortSeptember

Typical high24.6°C

Typical low15.5°C

Rain in September103 mm

Comfort

September

September · June · May

84climate match

Beach

July

July · August · June

83climate match

Outdoors

May

May · October · September

78climate match

The weakest month is January, scoring 5 against September’s 84 — days reach only 4.6°C, 19° 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

54.6° / -3.4°

Feb

55.4° / -2.9°

Mar

89.3° / 0.3°

Apr

4015.7° / 5.2°

May

7021.5° / 10.4°

Jun

7926.1° / 15.8°

Jul

6629.1° / 19.3°

Aug

6728.2° / 18.7°

Sep

8424.6° / 15.5°

Oct

5718.5° / 9.6°

Nov

3112.6° / 4.4°

Dec

57.4° / -0.2°

Monthly climate evidence for Riverhead — daylight is calculated from latitude, everything else is measured, sea temperature from the nearest open water 23 km away
Month	Day	Night	Rain	Wet days	Sea	Daylight	Comfort	Coverage
January	4.6°C	-3.4°C	97 mm	8.4	4.2°C	9 h 32	5	Strong coverage
February	5.4°C	-2.9°C	85 mm	7.3	2.4°C	10 h 34	5	Strong coverage
March	9.3°C	0.3°C	122 mm	8.3	3.2°C	11 h 49	8	Strong coverage
April	15.7°C	5.2°C	102 mm	9.4	6.7°C	13 h 14	40	Strong coverage
May	21.5°C	10.4°C	90 mm	9.2	11.7°C	14 h 26	70	Strong coverage
June	26.1°C	15.8°C	98 mm	7.6	17.0°C	15 h 06	79	Strong coverage
July	29.1°C	19.3°C	77 mm	6.9	21.2°C	14 h 50	66	Strong coverage
August	28.2°C	18.7°C	101 mm	7	22.3°C	13 h 48	67	Strong coverage
September	24.6°C	15.5°C	103 mm	7	21.1°C	12 h 25	84	Strong coverage
October	18.5°C	9.6°C	112 mm	7.4	17.7°C	11 h 02	57	Strong coverage
November	12.6°C	4.4°C	96 mm	7.4	12.8°C	9 h 50	31	Strong coverage
December	7.4°C	-0.2°C	115 mm	9.6	8.1°C	9 h 15	5	Strong coverage

What has changed

Riverhead runs +1.0°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

+1.4

Feb

+2.0

Mar

+1.3

Apr

+0.8

May

+0.5

Jun

+0.2

Jul

+1.0

Aug

+0.5

Sep

+1.0

Oct

+1.2

Nov

+0.7

Dec

+1.9

September daytime highs, 2011–2025. Last recorded: 25.4°C.

Records at RIVERHEAD RSCH FARM, 1938–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	20.0°C14 Jan 1995	-22.2°C18 Jan 1982	91 mm21 Jan 1979	315 mm1979 · driest 13 mm in 1970	87
February	20.0°C25 Feb 1976	-21.1°C15 Feb 1943	65 mm9 Feb 2013	169 mm2013 · driest 18 mm in 2026	88
March	28.3°C29 Mar 1945	-13.3°C19 Mar 1967	136 mm30 Mar 2010	340 mm2010 · driest 15 mm in 2006	89
April	33.3°C17 Apr 2002	-7.8°C7 Apr 1982	81 mm23 Apr 2006	291 mm1983 · driest 27 mm in 1942	88
May	35.6°C20 May 1996	-0.6°C2 May 1943	77 mm26 May 2003	210 mm1984 · driest 10 mm in 2015	89
June	36.7°C27 Jun 1952	3.9°C1 Jun 1938	134 mm5 Jun 1982	295 mm1982 · driest 1 mm in 1949	88
July	37.8°C6 Jul 1999	8.3°C1 Jul 1988	124 mm11 Jul 1959	226 mm1969 · driest 13 mm in 1944	88
August	37.2°C11 Aug 1944	7.2°C30 Aug 1986	175 mm7 Aug 1946	324 mm1946 · driest 10 mm in 1984	85
September	36.7°C2 Sep 1953	1.1°C30 Sep 1942	164 mm11 Sep 1954	298 mm1938 · driest 6 mm in 2024	87
October	32.8°C2 Oct 2019	-4.4°C31 Oct 1966	142 mm12 Oct 2005	516 mm2005 · driest 2 mm in 2024	86
November	26.7°C2 Nov 1950	-8.3°C22 Nov 1987	89 mm12 Nov 1947	239 mm1988 · driest 12 mm in 1976	87
December	24.4°C7 Dec 1998	-18.9°C20 Dec 1942	92 mm12 Dec 2008	218 mm1969 · driest 17 mm in 1955	87

Typical days per month at RIVERHEAD RSCH FARM, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)	Snow days
January	0	0	24	3	3
February	0	0	21	3	3
March	<1	0	15	4	2
April	1	<1	2	3	<1
May	8	1	0	3	0
June	20	5	0	3	0
July	29	12	0	3	0
August	28	9	0	3	0
September	15	2	0	3	0
October	2	0	<1	3	0
November	0	0	6	4	<1
December	0	0	17	4	2

How often, not how much — every day in RIVERHEAD RSCH FARM’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%	28%	11%	29%	0.9–7.0°C
February	0%	27%	11%	29%	1.8–8.0°C
March	2%	28%	11%	32%	6.5–11.7°C
April	15%	31%	11%	37%	12.7–17.0°C
May	49%	30%	11%	37%	19.0–23.4°C
June	73%	25%	9%	24%	24.4–27.5°C
July	76%	24%	9%	22%	27.2–30.3°C
August	77%	23%	9%	20%	26.4–29.2°C
September	70%	22%	9%	23%	22.6–25.6°C
October	31%	23%	9%	23%	16.8–20.5°C
November	4%	27%	12%	28%	10.3–14.4°C
December	<1%	29%	12%	33%	3.7–9.3°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.

1939Each stripe is one year’s mean temperature against the 78-year average. Warmest: 2023. Coolest: 1940.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 5133926
NOAA station: USC00307134 · RIVERHEAD RSCH FARM
Station distance: 6.8 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 28 usable years
Daylight: Calculated from latitude 40.92°, mid-month, sunrise to sunset including refraction. Not a station measurement.
Sea temperature: NOAA OISST v2.1 1991–2020 monthly climatology, nearest open water 23 km from the place centre. A sheltered bay can run warmer than the open sea it is measured from.
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 RIVERHEAD RSCH FARM is what differs

Mattituck→Aquebogue→Jamesport→Laurel→Northville→Centerville→

Or put two places side by side: Riverhead vs Mattituck

Best time to visitRiverhead.

September

July

May

The whole year,without the guesswork.

Riverhead runs +1.0°Con the 1961–1990 baseline.

Nearby, measured,and named.

Best time to visit
Riverhead.

The whole year,
without the guesswork.

Riverhead runs +1.0°C
on the 1961–1990 baseline.

Nearby, measured,
and named.