United States · 1991–2020

Best time to visit
Lafayette.

May leads for comfortable weather in Lafayette: typically 25.3°C by day, 11.8°C at night, with 14 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortMay

Typical high25.3°C

Typical low11.8°C

Rain in May14 mm

Comfort

May

May · October · April

90climate match

Beach

June

June · September · August

80climate match

Outdoors

April

April · March · November

91climate match

The weakest month is January, scoring 38 against May’s 90 — days reach only 14.4°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

3814.4° / 5.4°

Feb

4816.9° / 6.8°

Mar

6719.8° / 8.3°

Apr

8222° / 9.5°

May

9025.3° / 11.8°

Jun

8129° / 13.7°

Jul

7631° / 14.6°

Aug

7730.9° / 14.8°

Sep

8029.7° / 14.2°

Oct

9025.2° / 11.7°

Nov

6618.9° / 7.8°

Dec

3914.5° / 5.1°

Monthly climate evidence for Lafayette — daylight is calculated from latitude, everything else is measured, sea temperature from the nearest open water 45 km away
Month	Day	Night	Rain	Wet days	Sea	Daylight	Comfort	Coverage
January	14.4°C	5.4°C	93 mm	8.6	11.6°C	9 h 48	38	Strong coverage
February	16.9°C	6.8°C	95 mm	8.8	11.9°C	10 h 44	48	Strong coverage
March	19.8°C	8.3°C	60 mm	6.9	12.0°C	11 h 50	67	Strong coverage
April	22°C	9.5°C	33 mm	4.4	11.5°C	13 h 07	82	Strong coverage
May	25.3°C	11.8°C	14 mm	2.2	11.7°C	14 h 12	90	Strong coverage
June	29°C	13.7°C	4 mm	0.7	12.1°C	14 h 46	81	Strong coverage
July	31°C	14.6°C	0 mm	0	13.4°C	14 h 33	76	Strong coverage
August	30.9°C	14.8°C	1 mm	0.1	14.2°C	13 h 37	77	Strong coverage
September	29.7°C	14.2°C	2 mm	0.4	14.4°C	12 h 23	80	Strong coverage
October	25.2°C	11.7°C	19 mm	2.1	13.7°C	11 h 09	90	Strong coverage
November	18.9°C	7.8°C	47 mm	5.3	12.9°C	10 h 04	66	Strong coverage
December	14.5°C	5.1°C	88 mm	8.2	12.0°C	9 h 33	39	Strong coverage

Records at CONCORD WWTP, 1991–2019
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	24.4°C31 Jan 2015	-3.3°C14 Jan 2007	82 mm4 Jan 2008	258 mm1995 · driest 0 mm in 2015	28
February	26.1°C6 Feb 2018	-1.1°C26 Feb 2011	56 mm3 Feb 1998	283 mm1998 · driest 0 mm in 2018	28
March	30.0°C15 Mar 2004	1.1°C5 Mar 2018	38 mm6 Mar 2016	206 mm1995 · driest 3 mm in 2015	27
April	35.6°C27 Apr 2004	3.3°C9 Apr 1999	32 mm7 Apr 2018	97 mm2006 · driest 0 mm in 2008	27
May	38.3°C31 May 2001	5.0°C13 May 1999	30 mm16 May 1996	69 mm1998 · driest 0 mm in 2014	26
June	42.2°C14 Jun 2000	8.3°C19 Jun 2010	26 mm16 Jun 1995	44 mm2011 · driest 0 mm in 2003	27
July	43.3°C23 Jul 2006	10.6°C18 Jul 1999	1 mm22 Jul 2014	1 mm2014 · driest 0 mm in 1995	26
August	41.1°C25 Aug 2010	10.6°C27 Aug 2009	10 mm20 Aug 1997	10 mm1997 · driest 0 mm in 2001	27
September	43.3°C2 Sep 2017	8.3°C24 Sep 2015	18 mm20 Sep 2013	18 mm2013 · driest 0 mm in 1999	28
October	37.2°C4 Oct 1991	4.4°C31 Oct 1991	51 mm13 Oct 2009	74 mm2009 · driest 0 mm in 2013	27
November	30.0°C3 Nov 2018	-0.6°C29 Nov 2015	63 mm6 Nov 1994	140 mm1994 · driest 0 mm in 1995	27
December	23.3°C2 Dec 2011	-4.4°C24 Dec 1998	100 mm31 Dec 2005	299 mm2005 · driest 1 mm in 2017	27

Typical days per month at CONCORD WWTP, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)
January	0	0	2	3
February	<1	0	<1	4
March	4	0	0	2
April	7	1	0	1
May	15	5	0	<1
June	22	12	0	<1
July	27	18	0	0
August	26	16	0	0
September	24	13	0	0
October	15	4	0	<1
November	2	0	<1	2
December	0	0	2	3

How often, not how much — every day in CONCORD 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	3%	28%	10%	33%	12.7–16.1°C
February	18%	31%	14%	42%	14.9–18.9°C
March	46%	22%	7%	24%	17.2–21.9°C
April	64%	15%	4%	11%	19.9–23.9°C
May	86%	7%	1%	6%	23.0–27.9°C
June	97%	2%	<1%	<1%	26.9–30.7°C
July	100%	0%	0%	0%	29.3–33.0°C
August	100%	<1%	<1%	0%	29.5–32.3°C
September	99%	1%	<1%	<1%	28.1–31.2°C
October	88%	7%	2%	6%	23.3–27.4°C
November	34%	18%	5%	19%	16.9–20.3°C
December	1%	26%	10%	34%	12.8–15.9°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.

1992Each stripe is one year’s mean temperature against the 24-year average. Warmest: 2014. Coolest: 1999.2018

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 5364226
NOAA station: USC00041967 · CONCORD WWTP
Station distance: 11.7 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 26 usable years
Daylight: Calculated from latitude 37.89°, mid-month, sunrise to sunset including refraction. Not a station measurement.
Sea temperature: NOAA OISST v2.1 1991–2020 monthly climatology, nearest open water 45 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 CONCORD WWTP is what differs

Walnut Creek→Pleasant Hill→Waldon→Contra Costa Centre→Saranap→Pacheco→

Or put two places side by side: Lafayette vs Walnut Creek

Best time to visitLafayette.

May

June

April

The whole year,without the guesswork.

Nearby, measured,and named.

Best time to visit
Lafayette.

The whole year,
without the guesswork.

Nearby, measured,
and named.