United States · 1991–2020

Best time to visit
Hartley.

April leads for comfortable weather in Hartley: typically 23.4°C by day, 8.1°C at night, with 28 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortApril

Typical high23.4°C

Typical low8.1°C

Rain in April28 mm

Comfort

April

April · October · May

85climate match

Beach

May

May · June · September

70climate match

Outdoors

April

April · November · March

86climate match

The weakest month is January, scoring 25 against April’s 85 — days reach only 13.6°C, 10° 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

2513.6° / 3.8°

Feb

3716.6° / 5.3°

Mar

6220.2° / 6.6°

Apr

8523.4° / 8.1°

May

7928.3° / 11.1°

Jun

7132.2° / 13.7°

Jul

6035.9° / 15.1°

Aug

6235.4° / 14.5°

Sep

6832.9° / 13.4°

Oct

8227.2° / 10.5°

Nov

6219° / 6.5°

Dec

2513.7° / 3.8°

Monthly climate evidence for Hartley — daylight is calculated from latitude, everything else is measured
Month	Day	Night	Rain	Wet days	Daylight	Comfort	Coverage
January	13.6°C	3.8°C	141 mm	9.5	9 h 45	25	Good coverage
February	16.6°C	5.3°C	144 mm	9.2	10 h 42	37	Good coverage
March	20.2°C	6.6°C	82 mm	6.9	11 h 50	62	Good coverage
April	23.4°C	8.1°C	28 mm	3.4	13 h 09	85	Good coverage
May	28.3°C	11.1°C	24 mm	2.8	14 h 14	79	Good coverage
June	32.2°C	13.7°C	4 mm	0.8	14 h 50	71	Good coverage
July	35.9°C	15.1°C	0 mm	0.1	14 h 36	60	Good coverage
August	35.4°C	14.5°C	2 mm	0.2	13 h 39	62	Good coverage
September	32.9°C	13.4°C	1 mm	0.3	12 h 23	68	Good coverage
October	27.2°C	10.5°C	25 mm	2	11 h 08	82	Good coverage
November	19°C	6.5°C	64 mm	5	10 h 02	62	Good coverage
December	13.7°C	3.8°C	151 mm	8.6	9 h 30	25	Good coverage

Records at VACAVILLE, 1893–2009
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	27.2°C8 Jan 1962	-7.8°C5 Jan 1949	138 mm21 Jan 1967	503 mm1916 · driest 2 mm in 2007	105
February	27.8°C18 Feb 1899	-8.9°C5 Feb 1989	155 mm27 Feb 1940	385 mm1998 · driest 0 mm in 1953	108
March	32.2°C26 Mar 1988	-3.3°C21 Mar 1924	81 mm14 Mar 1910	271 mm1991 · driest 0 mm in 1923	106
April	37.2°C21 Apr 1949	-2.8°C15 Apr 1921	113 mm1 Apr 1927	179 mm1896 · driest 0 mm in 1924	105
May	42.8°C30 May 1910	-1.1°C2 May 1921	39 mm1 May 1905	97 mm1905 · driest 0 mm in 1954	103
June	46.1°C15 Jun 1961	2.2°C12 Jun 1919	24 mm2 Jun 1967	40 mm1967 · driest 0 mm in 1912	104
July	46.7°C23 Jul 2006	4.4°C1 Jul 1916	31 mm8 Jul 1974	31 mm1974 · driest 0 mm in 1901	102
August	45.6°C20 Aug 1950	3.9°C22 Aug 1955	29 mm21 Aug 2003	36 mm2003 · driest 0 mm in 1941	105
September	44.4°C2 Sep 1950	0.0°C19 Sep 1926	95 mm18 Sep 1959	97 mm1959 · driest 0 mm in 1952	104
October	41.7°C2 Oct 1933	-5.0°C29 Oct 1946	103 mm13 Oct 1962	208 mm1962 · driest 0 mm in 1905	103
November	32.8°C9 Nov 1955	-7.2°C18 Nov 1921	87 mm9 Nov 1927	227 mm1973 · driest 0 mm in 1933	107
December	25.6°C12 Dec 1958	-10.0°C26 Dec 1924	149 mm19 Dec 1955	467 mm2005 · driest 6 mm in 2009	105

Typical days per month at VACAVILLE, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)
January	<1	0	5	4
February	<1	0	2	5
March	5	<1	<1	3
April	11	3	<1	<1
May	21	12	0	<1
June	27	20	0	<1
July	29	28	0	0
August	29	27	0	<1
September	28	23	0	0
October	20	9	0	<1
November	2	<1	<1	2
December	0	0	5	4

How often, not how much — every day in VACAVILLE’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	3%	31%	15%	38%	10.6–15.0°C
February	16%	29%	14%	35%	14.3–18.3°C
March	42%	25%	11%	26%	16.7–22.2°C
April	69%	14%	4%	11%	20.1–25.5°C
May	89%	7%	2%	4%	24.0–29.9°C
June	98%	2%	<1%	<1%	28.7–34.1°C
July	100%	<1%	0%	0%	33.3–37.4°C
August	99%	<1%	0%	<1%	32.5–36.7°C
September	97%	3%	<1%	2%	29.6–34.0°C
October	88%	9%	3%	6%	24.0–28.8°C
November	41%	19%	9%	23%	16.3–22.0°C
December	4%	27%	12%	31%	11.0–15.9°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.

1905Each stripe is one year’s mean temperature against the 88-year average. Warmest: 1997. Coolest: 1948.2008

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 5355612
NOAA station: USC00049200 · VACAVILLE
Station distance: 2.7 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 17 usable years
Daylight: Calculated from latitude 38.42°, 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 VACAVILLE is what differs

Allendale→Batavia→Bucktown→

Or put two places side by side: Hartley vs Allendale

Best time to visitHartley.

April

May

April

The whole year,without the guesswork.

Nearby, measured,and named.

Best time to visit
Hartley.

The whole year,
without the guesswork.

Nearby, measured,
and named.