United States · 1991–2020

Best time to visit
Niwot.

September leads for comfortable weather in Niwot: typically 26.6°C by day, 7.1°C at night, with 34 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortSeptember

Typical high26.6°C

Typical low7.1°C

Rain in September34 mm

Comfort

September

September · May · June

75climate match

Beach

July

July · August · June

67climate match

Outdoors

October

October · May · September

78climate match

The weakest month is January, scoring 5 against September’s 75 — days reach only 7.2°C, 17° below the 24°C the score treats as ideal, and nights drop to -10.1°C.

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

57.2° / -10.1°

Feb

68.4° / -8.7°

Mar

2913.4° / -4.3°

Apr

4517.3° / -0.2°

May

7122.8° / 5.5°

Jun

7128.4° / 9.8°

Jul

6832.1° / 13.1°

Aug

6831.1° / 11.9°

Sep

7526.6° / 7.1°

Oct

5519° / -0.1°

Nov

2011.2° / -5.4°

Dec

58° / -9.2°

Monthly climate evidence for Niwot — daylight is calculated from latitude, everything else is measured
Month	Day	Night	Rain	Wet days	Daylight	Comfort	Coverage
January	7.2°C	-10.1°C	12 mm	3.2	9 h 36	5	Good coverage
February	8.4°C	-8.7°C	12 mm	3.1	10 h 37	6	Good coverage
March	13.4°C	-4.3°C	35 mm	4.4	11 h 49	29	Good coverage
April	17.3°C	-0.2°C	52 mm	6.7	13 h 12	45	Good coverage
May	22.8°C	5.5°C	61 mm	7.5	14 h 22	71	Good coverage
June	28.4°C	9.8°C	49 mm	6.6	15 h 00	71	Good coverage
July	32.1°C	13.1°C	33 mm	4.7	14 h 45	68	Good coverage
August	31.1°C	11.9°C	42 mm	5.4	13 h 45	68	Good coverage
September	26.6°C	7.1°C	34 mm	4.9	12 h 24	75	Good coverage
October	19°C	-0.1°C	23 mm	4.1	11 h 04	55	Good coverage
November	11.2°C	-5.4°C	22 mm	4.2	9 h 54	20	Good coverage
December	8°C	-9.2°C	7 mm	2.2	9 h 20	5	Good coverage

What has changed

Niwot runs +0.9°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

+0.5

Feb

-1.5

Mar

+1.5

Apr

+0.8

May

+0.1

Jun

+1.5

Jul

+0.5

Aug

+0.9

Sep

+2.2

Oct

-0.6

Nov

+1.8

Dec

+3.2

September daytime highs, 2017–2025. Last recorded: 26.2°C.

Records at LONGMONT 2 ESE, 1893–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	23.9°C27 Jan 1982	-38.9°C16 Jan 1930	19 mm20 Jan 1973	34 mm1996 · driest 0 mm in 1952	109
February	26.1°C27 Feb 1932	-37.8°C1 Feb 1951	26 mm27 Feb 1931	45 mm2024 · driest 0 mm in 1992	107
March	33.3°C26 Mar 2026	-32.2°C8 Mar 1932	52 mm9 Mar 1992	119 mm1983 · driest 1 mm in 1910	108
April	32.8°C23 Apr 2022	-21.7°C2 Apr 1975	94 mm18 Apr 1920	132 mm1920 · driest 0 mm in 1925	108
May	37.8°C30 May 2003	-7.8°C1 May 1989	117 mm30 May 1896	178 mm1995 · driest 2 mm in 1974	108
June	41.1°C27 Jun 1994	-1.7°C6 Jun 1998	112 mm3 Jun 1921	161 mm1921 · driest 0 mm in 1971	107
July	41.1°C7 Jul 1973	3.3°C20 Jul 1994	85 mm19 Jul 1946	125 mm1918 · driest 0 mm in 1939	107
August	40.0°C8 Aug 1995	2.8°C27 Aug 1992	51 mm9 Aug 1930	121 mm1992 · driest 0 mm in 1971	106
September	38.3°C6 Sep 2020	-7.8°C30 Sep 1985	88 mm3 Sep 1938	154 mm1938 · driest 0 mm in 1943	107
October	33.3°C17 Oct 1926	-20.6°C28 Oct 1917	71 mm14 Oct 1916	122 mm1969 · driest 0 mm in 1934	107
November	28.3°C2 Nov 1931	-26.7°C27 Nov 1952	28 mm26 Nov 2019	63 mm1983 · driest 0 mm in 1949	106
December	25.6°C11 Dec 1939	-35.6°C23 Dec 1924	62 mm4 Dec 1913	108 mm1913 · driest 0 mm in 1935	105

Typical days per month at LONGMONT 2 ESE, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)	Snow days
January	0	0	29	<1	2
February	<1	0	27	<1	3
March	<1	0	26	<1	2
April	5	<1	16	2	2
May	14	4	3	2	<1
June	23	13	<1	2	0
July	29	23	0	<1	0
August	28	21	0	1	0
September	21	11	2	1	<1
October	7	1	14	<1	1
November	<1	0	26	<1	2
December	0	0	29	0	1

How often, not how much — every day in LONGMONT 2 ESE’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%	9%	<1%	2%	1.6–9.6°C
February	4%	11%	<1%	6%	3.6–11.6°C
March	16%	15%	2%	9%	8.0–15.7°C
April	38%	19%	4%	15%	13.6–20.2°C
May	59%	23%	6%	25%	19.3–24.7°C
June	78%	19%	4%	15%	25.3–30.8°C
July	83%	16%	3%	13%	29.6–33.4°C
August	84%	16%	3%	11%	28.7–32.2°C
September	78%	14%	3%	10%	23.6–28.4°C
October	53%	12%	2%	8%	16.3–21.9°C
November	14%	11%	1%	4%	8.1–14.8°C
December	2%	8%	<1%	4%	3.4–10.1°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.

1895Each stripe is one year’s mean temperature against the 100-year average. Warmest: 2024. Coolest: 1912.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 5580305
NOAA station: USC00055116 · LONGMONT 2 ESE
Station distance: 10.8 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 16 usable years
Daylight: Calculated from latitude 40.10°, 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 LONGMONT 2 ESE is what differs

Longmont→Erie→Firestone→Frederick→Dacono→Mead→

Or put two places side by side: Niwot vs Longmont

Best time to visitNiwot.