United States · 1991–2020

Best time to visit
Bethel Island.

October leads for comfortable weather in Bethel Island: typically 25.4°C by day, 12°C at night, with 10 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortOctober

Typical high25.4°C

Typical low12°C

Rain in October10 mm

Comfort

October

October · May · April

90climate match

Beach

June

June · September · August

78climate match

Outdoors

April

April · November · March

92climate match

The weakest month is January, scoring 35 against October’s 90 — days reach only 13.3°C, 11° 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

3513.3° / 4.3°

Feb

5016.3° / 6.3°

Mar

6519.2° / 7.8°

Apr

8522.4° / 9.5°

May

8826.2° / 12.1°

Jun

7830.3° / 14.7°

Jul

6933.1° / 15.5°

Aug

7232.3° / 15.3°

Sep

7830.4° / 14.5°

Oct

9025.4° / 12°

Nov

6718.3° / 7.5°

Dec

3713.3° / 4.5°

Monthly climate evidence for Bethel Island — daylight is calculated from latitude, everything else is measured
Month	Day	Night	Rain	Wet days	Daylight	Comfort	Coverage
January	13.3°C	4.3°C	77 mm	8.3	9 h 48	35	Good coverage
February	16.3°C	6.3°C	68 mm	7.3	10 h 43	50	Good coverage
March	19.2°C	7.8°C	54 mm	7.3	11 h 50	65	Good coverage
April	22.4°C	9.5°C	19 mm	2.9	13 h 08	85	Good coverage
May	26.2°C	12.1°C	10 mm	1.7	14 h 12	88	Good coverage
June	30.3°C	14.7°C	2 mm	0.5	14 h 47	78	Good coverage
July	33.1°C	15.5°C	0 mm	0	14 h 33	69	Strong coverage
August	32.3°C	15.3°C	0 mm	0.1	13 h 38	72	Strong coverage
September	30.4°C	14.5°C	1 mm	0.3	12 h 23	78	Strong coverage
October	25.4°C	12°C	10 mm	1.2	11 h 08	90	Strong coverage
November	18.3°C	7.5°C	32 mm	3.6	10 h 04	67	Good coverage
December	13.3°C	4.5°C	70 mm	6.8	9 h 32	37	Good coverage

What has changed

Bethel Island runs +1.4°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

+3.3

Feb

+1.9

Mar

+1.6

Apr

+2.1

May

+0.5

Jun

+1.6

Jul

+0.2

Aug

+0.1

Sep

+0.9

Oct

—

Nov

+1.5

Dec

+2.1

October daytime highs, 2011–2020. Last recorded: 28.7°C.

Records at ANTIOCH PUMPING PLT #3, 1955–2021
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	26.1°C26 Jan 2012	-6.7°C24 Jan 1962	71 mm5 Jan 1982	177 mm1993 · driest 1 mm in 2015	62
February	26.1°C9 Feb 2011	-3.9°C6 Feb 1989	59 mm3 Feb 1998	229 mm1998 · driest 0 mm in 2020	62
March	31.1°C27 Mar 1988	-2.8°C4 Mar 1966	36 mm3 Mar 2009	159 mm1983 · driest 1 mm in 1956	61
April	34.4°C21 Apr 2009	-2.2°C19 Apr 1961	37 mm3 Apr 1958	101 mm1958 · driest 0 mm in 2021	64
May	40.0°C6 May 2011	0.0°C18 May 2011	28 mm16 May 1996	53 mm1998 · driest 0 mm in 1970	64
June	47.2°C17 Jun 1961	1.7°C18 Jun 1979	20 mm9 Jun 1964	20 mm1964 · driest 0 mm in 1959	62
July	43.3°C11 Jul 1961	5.0°C5 Jul 1961	10 mm2 Jul 1980	12 mm1980 · driest 0 mm in 1977	63
August	42.8°C5 Aug 1998	4.4°C5 Aug 1983	11 mm22 Aug 1968	19 mm1976 · driest 0 mm in 1972	64
September	43.3°C7 Sep 2020	5.0°C14 Sep 1980	32 mm19 Sep 1959	47 mm1989 · driest 0 mm in 1993	64
October	38.9°C5 Oct 1964	-2.2°C30 Oct 1971	77 mm13 Oct 1962	123 mm1962 · driest 0 mm in 2002	62
November	30.6°C1 Nov 2011	-4.4°C17 Nov 1958	59 mm17 Nov 1996	123 mm1970 · driest 0 mm in 1986	61
December	23.9°C2 Dec 2011	-7.8°C11 Dec 1972	71 mm11 Dec 2014	211 mm2014 · driest 0 mm in 1989	64

Typical days per month at ANTIOCH PUMPING PLT #3, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)
January	<1	0	4	2
February	<1	0	<1	2
March	2	0	0	1
April	9	2	0	<1
May	18	7	0	<1
June	25	16	0	<1
July	30	26	0	0
August	29	23	0	0
September	27	16	0	0
October	16	5	0	<1
November	2	0	<1	<1
December	0	0	3	2

The best month has moved. On the 1961–1990 numbers the strongest month here was May (scoring 85); on 2011–2025 it is April (92). Both are scored the same way, from the same station — only the climate underneath changed.

How often, not how much — every day in ANTIOCH PUMPING PLT #3’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%	24%	7%	31%	10.0–14.5°C
February	12%	24%	7%	30%	13.9–18.0°C
March	37%	22%	5%	22%	16.5–21.0°C
April	66%	11%	2%	8%	19.4–24.9°C
May	89%	5%	<1%	2%	23.8–28.3°C
June	98%	1%	<1%	<1%	27.5–31.9°C
July	100%	<1%	<1%	0%	31.3–34.9°C
August	99%	<1%	<1%	<1%	30.9–34.0°C
September	98%	2%	<1%	<1%	28.4–31.9°C
October	88%	5%	2%	4%	23.1–27.7°C
November	32%	15%	4%	17%	15.7–20.4°C
December	3%	20%	6%	24%	10.7–15.0°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.

1956Each stripe is one year’s mean temperature against the 46-year average. Warmest: 2014. Coolest: 1971.2020

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 5327951
NOAA station: USC00040232 · ANTIOCH PUMPING PLT #3
Station distance: 10.4 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 20 usable years
Daylight: Calculated from latitude 38.01°, 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 ANTIOCH PUMPING PLT #3 is what differs

Antioch→Pittsburg→Brentwood→Oakley→Rio Vista→Knightsen→

Or put two places side by side: Bethel Island vs Antioch

Best time to visitBethel Island.