United States · 1991–2020

Best time to visit
San Lorenzo.

July leads for comfortable weather in San Lorenzo: typically 23.7°C by day, 14.3°C at night, with 0 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortJuly

Typical high23.7°C

Typical low14.3°C

Rain in July0 mm

Comfort

July

July · August · September

98climate match

Beach

August

August · September · July

68climate match

Outdoors

May

May · April · November

96climate match

The weakest month is December, scoring 44 against July’s 98 — days reach only 14.9°C, 9° 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

4614.8° / 6.2°

Feb

5116.1° / 7.2°

Mar

6017.7° / 8.5°

Apr

7218.8° / 9.7°

May

8220.5° / 11.6°

Jun

9322.8° / 13.1°

Jul

9823.7° / 14.3°

Aug

9824° / 14.8°

Sep

9624.7° / 14.3°

Oct

9022.5° / 12.2°

Nov

6617.9° / 8.6°

Dec

4414.9° / 6.2°

Monthly climate evidence for San Lorenzo — daylight is calculated from latitude, everything else is measured, sea temperature from the nearest open water 40 km away
Month	Day	Night	Rain	Wet days	Sea	Daylight	Comfort	Coverage
January	14.8°C	6.2°C	58 mm	7.5	12.2°C	9 h 49	46	Good coverage
February	16.1°C	7.2°C	68 mm	7.9	12.3°C	10 h 44	51	Good coverage
March	17.7°C	8.5°C	54 mm	7.8	12.3°C	11 h 50	60	Good coverage
April	18.8°C	9.7°C	33 mm	4.7	12.0°C	13 h 07	72	Good coverage
May	20.5°C	11.6°C	12 mm	2.3	12.2°C	14 h 11	82	Good coverage
June	22.8°C	13.1°C	4 mm	0.5	12.9°C	14 h 45	93	Good coverage
July	23.7°C	14.3°C	0 mm	0	14.1°C	14 h 32	98	Good coverage
August	24°C	14.8°C	0 mm	0.1	14.9°C	13 h 37	98	Good coverage
September	24.7°C	14.3°C	3 mm	0.5	14.9°C	12 h 23	96	Good coverage
October	22.5°C	12.2°C	20 mm	2.2	14.2°C	11 h 09	90	Good coverage
November	17.9°C	8.6°C	36 mm	5.1	13.4°C	10 h 05	66	Good coverage
December	14.9°C	6.2°C	75 mm	7.8	12.5°C	9 h 34	44	Good coverage

Records at HAYWARD AIR TERMINAL, 1998–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	26.1°C18 Jan 2021	-2.2°C15 Jan 2007	50 mm24 Jan 2000	203 mm2023 · driest 0 mm in 2015	28
February	27.2°C3 Feb 2018	0.6°C27 Feb 2011	54 mm13 Feb 2000	180 mm2000 · driest 0 mm in 2020	28
March	31.1°C20 Mar 2026	2.2°C8 Mar 2002	33 mm24 Mar 2011	161 mm2023 · driest 3 mm in 2015	28
April	35.0°C20 Apr 2009	2.2°C9 Apr 1999	36 mm20 Apr 2026	112 mm2026 · driest 2 mm in 2021	28
May	37.2°C15 May 2008	5.0°C11 May 2022	23 mm4 May 2024	59 mm2019 · driest 0 mm in 2017	28
June	40.0°C14 Jun 2000	8.3°C5 Jun 2014	23 mm28 Jun 2011	46 mm2011 · driest 0 mm in 2016	28
July	40.6°C22 Jul 2006	11.7°C7 Jul 1999	0 mm13 Jul 2011	0 mm2011 · driest 0 mm in 1999	28
August	39.4°C14 Aug 2020	11.7°C11 Aug 2012	3 mm6 Aug 1999	5 mm1999 · driest 0 mm in 2006	27
September	42.2°C2 Sep 2017	8.3°C26 Sep 2013	11 mm13 Sep 2009	12 mm2009 · driest 0 mm in 2003	27
October	38.9°C6 Oct 2024	6.1°C31 Oct 2002	84 mm24 Oct 2021	128 mm2021 · driest 0 mm in 2018	28
November	29.4°C14 Nov 2008	0.6°C25 Nov 2010	43 mm8 Nov 2022	87 mm2025 · driest 11 mm in 2020	28
December	24.4°C7 Dec 2020	-2.8°C23 Dec 1998	110 mm31 Dec 2022	268 mm2022 · driest 1 mm in 2017	28

Typical days per month at HAYWARD AIR TERMINAL, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)
January	<1	0	<1	2
February	<1	0	0	2
March	2	<1	0	2
April	3	<1	0	1
May	5	2	0	<1
June	8	3	0	<1
July	10	2	0	0
August	10	2	0	0
September	12	5	0	0
October	9	2	0	<1
November	<1	0	0	1
December	0	0	<1	3

How often, not how much — every day in HAYWARD AIR TERMINAL’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	6%	24%	7%	28%	13.4–16.7°C
February	15%	27%	9%	38%	14.4–18.4°C
March	25%	25%	6%	27%	15.6–19.8°C
April	32%	15%	4%	14%	17.4–20.5°C
May	47%	7%	<1%	5%	18.9–22.9°C
June	74%	2%	<1%	0%	21.2–24.4°C
July	89%	0%	0%	0%	22.3–25.4°C
August	94%	<1%	0%	0%	22.9–25.8°C
September	89%	2%	<1%	<1%	22.9–26.5°C
October	72%	7%	2%	6%	20.6–24.8°C
November	25%	17%	3%	16%	16.2–19.2°C
December	3%	27%	10%	37%	13.5–16.9°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.

1999Each stripe is one year’s mean temperature against the 26-year average. Warmest: 2024. Coolest: 1999.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 5392281
NOAA station: USW00093228 · HAYWARD AIR TERMINAL
Station distance: 2 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 22 usable years
Daylight: Calculated from latitude 37.67°, mid-month, sunrise to sunset including refraction. Not a station measurement.
Sea temperature: NOAA OISST v2.1 1991–2020 monthly climatology, nearest open water 40 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 HAYWARD AIR TERMINAL is what differs

Hayward→Castro Valley→Ashland→Cherryland→Fairview→Longwood - Winton Grove→

Or put two places side by side: San Lorenzo vs Hayward

Best time to visitSan Lorenzo.

July

August

May

The whole year,without the guesswork.

Nearby, measured,and named.

Best time to visit
San Lorenzo.

The whole year,
without the guesswork.

Nearby, measured,
and named.