United States · 1991–2020

Best time to visit
Rail Road Flat.

September leads for comfortable weather in Rail Road Flat: typically 23.1°C by day, 9.9°C at night, with 11 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortSeptember

Typical high23.1°C

Typical low9.9°C

Rain in September11 mm

Comfort

September

September · July · August

88climate match

Beach

July

July · August · September

71climate match

Outdoors

June

June · September · October

90climate match

The weakest month is January, scoring 5 against September’s 88 — days reach only 7.3°C, 17° below the 24°C the score treats as ideal, and 280 mm of rain falls.

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

57.3° / -1.2°

Feb

57.6° / -1.3°

Mar

59.3° / -0.5°

Apr

2112.2° / 1.3°

May

5216.9° / 5.3°

Jun

8522.7° / 9.1°

Jul

8726.8° / 12.8°

Aug

8726.6° / 12.5°

Sep

8823.1° / 9.9°

Oct

5617.5° / 5.7°

Nov

1510.9° / 1°

Dec

56.6° / -1.5°

Monthly climate evidence for Rail Road Flat — daylight is calculated from latitude, everything else is measured
Month	Day	Night	Rain	Wet days	Daylight	Comfort	Coverage
January	7.3°C	-1.2°C	280 mm	10.4	9 h 46	5	Strong coverage
February	7.6°C	-1.3°C	252 mm	10.1	10 h 42	5	Strong coverage
March	9.3°C	-0.5°C	226 mm	10.1	11 h 50	5	Strong coverage
April	12.2°C	1.3°C	122 mm	6.6	13 h 08	21	Strong coverage
May	16.9°C	5.3°C	73 mm	5	14 h 14	52	Strong coverage
June	22.7°C	9.1°C	18 mm	1.8	14 h 49	85	Strong coverage
July	26.8°C	12.8°C	3 mm	0.3	14 h 35	87	Strong coverage
August	26.6°C	12.5°C	1 mm	0.2	13 h 39	87	Strong coverage
September	23.1°C	9.9°C	11 mm	1.4	12 h 23	88	Strong coverage
October	17.5°C	5.7°C	75 mm	3.2	11 h 08	56	Strong coverage
November	10.9°C	1°C	128 mm	6.5	10 h 02	15	Strong coverage
December	6.6°C	-1.5°C	248 mm	10	9 h 30	5	Strong coverage

What has changed

Rail Road Flat runs -0.1°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

+0.9

Feb

+0.2

Mar

-0.9

Apr

+1.2

May

-1.0

Jun

-0.6

Jul

-1.1

Aug

-0.6

Sep

-0.2

Oct

0.0

Nov

0.0

Dec

+0.7

September daytime highs, 2011–2022. Last recorded: 24.3°C.

Records at CALAVERAS BIG TREES, 1929–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	22.8°C18 Jan 1931	-17.2°C20 Jan 1937	199 mm2 Jan 1997	863 mm1969 · driest 1 mm in 2015	95
February	27.8°C16 Feb 1930	-16.1°C27 Feb 1962	206 mm1 Feb 1963	923 mm1986 · driest 0 mm in 1953	93
March	27.8°C25 Mar 1930	-13.3°C3 Mar 1951	138 mm22 Mar 2018	643 mm1995 · driest 0 mm in 1934	93
April	31.1°C20 Apr 1931	-9.4°C28 Apr 1970	115 mm11 Apr 1982	437 mm1935 · driest 0 mm in 1959	92
May	33.9°C29 May 1984	-6.1°C31 May 1930	116 mm19 May 1957	220 mm1957 · driest 0 mm in 1937	92
June	37.8°C27 Jun 1942	-6.1°C1 Jun 1930	54 mm7 Jun 1936	98 mm1936 · driest 0 mm in 1960	93
July	41.7°C27 Jul 1933	-0.6°C17 Jul 1987	55 mm10 Jul 1974	89 mm1974 · driest 0 mm in 1998	91
August	41.1°C24 Aug 1931	0.0°C21 Aug 1968	56 mm15 Aug 1976	91 mm1976 · driest 0 mm in 2006	91
September	41.1°C9 Sep 1932	-2.2°C27 Sep 1971	114 mm19 Sep 1959	132 mm1959 · driest 0 mm in 1995	90
October	34.4°C4 Oct 1932	-6.7°C29 Oct 1971	156 mm24 Oct 2021	325 mm2016 · driest 0 mm in 1932	92
November	31.7°C1 Nov 1930	-12.8°C22 Nov 1931	170 mm18 Nov 1950	609 mm1983 · driest 0 mm in 1929	89
December	25.6°C3 Dec 1958	-17.8°C11 Dec 1932	202 mm11 Dec 1937	869 mm1955 · driest 0 mm in 1989	94

Typical days per month at CALAVERAS BIG TREES, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)	Snow days
January	0	0	20	6	5
February	0	0	18	6	5
March	0	0	17	6	5
April	0	0	12	4	3
May	2	0	4	2	1
June	11	1	<1	<1	0
July	23	4	0	0	0
August	22	4	0	0	0
September	12	<1	<1	<1	0
October	2	<1	2	2	<1
November	0	0	13	4	2
December	0	0	21	6	4

The best month has moved. On the 1961–1990 numbers the strongest month here was June (scoring 86); on 2011–2025 it is September (92). Both are scored the same way, from the same station — only the climate underneath changed.

How often, not how much — every day in CALAVERAS BIG TREES’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%	31%	21%	40%	4.9–10.8°C
February	2%	34%	21%	43%	5.0–12.6°C
March	5%	32%	20%	37%	6.6–14.5°C
April	18%	23%	13%	26%	9.6–17.6°C
May	45%	15%	6%	14%	14.6–21.5°C
June	78%	6%	2%	3%	20.4–26.8°C
July	98%	1%	<1%	<1%	25.5–30.6°C
August	97%	1%	<1%	<1%	25.3–30.4°C
September	82%	5%	2%	3%	21.6–27.0°C
October	44%	12%	7%	12%	15.3–22.5°C
November	9%	22%	13%	28%	8.0–15.3°C
December	2%	29%	19%	35%	4.6–12.2°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.

1930Each stripe is one year’s mean temperature against the 80-year average. Warmest: 1931. Coolest: 1998.2019

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 5385632
NOAA station: USC00041277 · CALAVERAS BIG TREES
Station distance: 19.2 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 26 usable years
Daylight: Calculated from latitude 38.34°, 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 CALAVERAS BIG TREES is what differs

Arnold→Forest Meadows→West Point→Avery→Fort Jones→Dorrington→

Or put two places side by side: Rail Road Flat vs Arnold

Best time to visitRail Road Flat.