United States · 1991–2020

Best time to visit
Norwalk.

September leads for comfortable weather in Norwalk: typically 24.2°C by day, 12.5°C at night, with 90 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortSeptember

Typical high24.2°C

Typical low12.5°C

Rain in September90 mm

Comfort

September

September · June · August

83climate match

Beach

July

July · August · June

69climate match

Outdoors

May

May · October · September

75climate match

The weakest month is January, scoring 5 against September’s 83 — days reach only 0.8°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

50.8° / -7.2°

Feb

52.3° / -6.4°

Mar

57.5° / -2.3°

Apr

3214.8° / 3.4°

May

6621.3° / 10°

Jun

7526.3° / 15.4°

Jul

6628.3° / 17.6°

Aug

7427.4° / 16.4°

Sep

8324.2° / 12.5°

Oct

5017.4° / 6.3°

Nov

179.8° / 0.9°

Dec

53.6° / -3.8°

Monthly climate evidence for Norwalk — daylight is calculated from latitude, everything else is measured, sea temperature from the nearest open water 43 km away
Month	Day	Night	Rain	Wet days	Sea	Daylight	Comfort	Coverage
January	0.8°C	-7.2°C	68 mm	10.6	1.3°C	9 h 30	5	Strong coverage
February	2.3°C	-6.4°C	59 mm	8.5	0.6°C	10 h 33	5	Strong coverage
March	7.5°C	-2.3°C	74 mm	9.9	1.6°C	11 h 48	5	Strong coverage
April	14.8°C	3.4°C	101 mm	11.2	5.7°C	13 h 15	32	Strong coverage
May	21.3°C	10°C	99 mm	11.2	12.2°C	14 h 28	66	Strong coverage
June	26.3°C	15.4°C	109 mm	10	19.3°C	15 h 08	75	Strong coverage
July	28.3°C	17.6°C	107 mm	9.1	23.7°C	14 h 52	66	Strong coverage
August	27.4°C	16.4°C	90 mm	8.5	24.0°C	13 h 49	74	Strong coverage
September	24.2°C	12.5°C	90 mm	8	21.5°C	12 h 25	83	Strong coverage
October	17.4°C	6.3°C	84 mm	8.9	15.4°C	11 h 02	50	Strong coverage
November	9.8°C	0.9°C	72 mm	8.7	8.7°C	9 h 49	17	Strong coverage
December	3.6°C	-3.8°C	66 mm	9.9	3.9°C	9 h 13	5	Strong coverage

What has changed

Norwalk runs +0.8°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

+0.7

Feb

+1.1

Mar

+1.0

Apr

+0.4

May

+0.9

Jun

+0.6

Jul

+0.6

Aug

+0.5

Sep

+1.1

Oct

+1.0

Nov

-0.1

Dec

+2.0

September daytime highs, 2011–2025. Last recorded: 25.6°C.

Records at NORWALK WWTP, 1894–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	22.2°C21 Jan 1906	-30.6°C13 Jan 1912	71 mm21 Jan 1959	200 mm1937 · driest 0 mm in 2025	132
February	23.9°C25 Feb 2017	-31.7°C20 Feb 1929	62 mm10 Feb 1959	152 mm2008 · driest 0 mm in 2024	132
March	29.4°C24 Mar 1910	-26.1°C12 Mar 1948	74 mm25 Mar 1913	272 mm1913 · driest 7 mm in 1910	133
April	33.3°C17 Apr 1896	-13.9°C7 Apr 1982	63 mm4 Apr 1934	206 mm1961 · driest 16 mm in 1952	133
May	36.7°C28 May 1911	-7.2°C21 May 1895	73 mm12 May 1956	188 mm1956 · driest 15 mm in 1988	133
June	39.4°C1 Jun 1934	-1.7°C6 Jun 1894	138 mm22 Jun 2006	258 mm1937 · driest 6 mm in 1988	132
July	42.2°C24 Jul 1934	1.1°C4 Jul 1895	229 mm5 Jul 1969	323 mm1977 · driest 22 mm in 1930	130
August	40.0°C6 Aug 1918	1.7°C25 Aug 1951	111 mm12 Aug 1948	235 mm1919 · driest 11 mm in 1970	130
September	38.9°C14 Sep 1939	-5.0°C23 Sep 1896	91 mm9 Sep 1990	247 mm1910 · driest 9 mm in 1908	131
October	33.3°C11 Oct 1928	-11.1°C30 Oct 1895	67 mm30 Oct 2012	220 mm2012 · driest 2 mm in 1963	132
November	27.8°C1 Nov 1933	-18.9°C30 Nov 1958	71 mm17 Nov 1958	184 mm1983 · driest 4 mm in 1904	132
December	22.8°C4 Dec 1982	-27.2°C22 Dec 1989	80 mm1 Dec 2006	172 mm1990 · driest 7 mm in 1958	132

Typical days per month at NORWALK WWTP, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)	Snow days
January	0	0	27	2	8
February	0	0	25	2	6
March	<1	0	22	2	4
April	3	<1	8	4	<1
May	10	3	<1	4	0
June	19	8	0	4	0
July	26	11	0	3	0
August	24	8	0	3	0
September	14	4	0	3	0
October	4	<1	3	2	0
November	<1	0	14	3	1
December	0	0	24	2	5

How often, not how much — every day in NORWALK WWTP’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%	30%	6%	34%	-2.4–5.2°C
February	<1%	28%	6%	32%	-1.5–5.9°C
March	5%	31%	8%	39%	4.5–12.1°C
April	18%	36%	10%	48%	12.4–17.7°C
May	41%	35%	10%	47%	18.9–24.7°C
June	63%	32%	12%	37%	24.6–29.0°C
July	71%	28%	11%	31%	27.0–31.4°C
August	73%	26%	9%	27%	26.0–30.1°C
September	62%	27%	10%	28%	22.2–26.6°C
October	31%	26%	7%	27%	15.4–20.5°C
November	5%	29%	7%	34%	7.4–12.7°C
December	<1%	30%	6%	36%	-0.1–6.6°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.

1896Each stripe is one year’s mean temperature against the 121-year average. Warmest: 1921. Coolest: 1917.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 5165101
NOAA station: USC00336118 · NORWALK WWTP
Station distance: 2.3 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 29 usable years
Daylight: Calculated from latitude 41.24°, mid-month, sunrise to sunset including refraction. Not a station measurement.
Sea temperature: NOAA OISST v2.1 1991–2020 monthly climatology, nearest open water 43 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 NORWALK WWTP is what differs

Bellevue→Willard→Monroeville→Milan→Berlin Heights→Collins→

Or put two places side by side: Norwalk vs Bellevue

Best time to visitNorwalk.

September

July

May

The whole year,without the guesswork.

Norwalk runs +0.8°Con the 1961–1990 baseline.

Nearby, measured,and named.

Best time to visit
Norwalk.

The whole year,
without the guesswork.

Norwalk runs +0.8°C
on the 1961–1990 baseline.

Nearby, measured,
and named.