United States · 1991–2020

Best time to visit
Monte Rio.

May leads for comfortable weather in Monte Rio: typically 24.4°C by day, 7°C at night, with 36 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortMay

Typical high24.4°C

Typical low7°C

Rain in May36 mm

Comfort

May

May · June · July

84climate match

Beach

August

August · July · September

68climate match

Outdoors

May

May · April · June

81climate match

The weakest month is December, scoring 14 against May’s 84 — days reach only 14.7°C, 9° below the 24°C the score treats as ideal, and 212 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

1714.9° / 2.4°

Feb

2917.2° / 3.4°

Mar

4619.3° / 4.3°

Apr

6821.6° / 5.2°

May

8424.4° / 7°

Jun

7627.8° / 8.5°

Jul

7628.5° / 9.8°

Aug

7329.2° / 9.6°

Sep

7129.2° / 8.4°

Oct

7526.1° / 6.3°

Nov

5119.8° / 3.7°

Dec

1414.7° / 2.1°

Monthly climate evidence for Monte Rio — daylight is calculated from latitude, everything else is measured, sea temperature from the nearest open water 14 km away
Month	Day	Night	Rain	Wet days	Sea	Daylight	Comfort	Coverage
January	14.9°C	2.4°C	200 mm	11	11.5°C	9 h 45	17	Strong coverage
February	17.2°C	3.4°C	190 mm	10	11.7°C	10 h 42	29	Strong coverage
March	19.3°C	4.3°C	132 mm	9.6	11.5°C	11 h 50	46	Strong coverage
April	21.6°C	5.2°C	66 mm	5.8	10.7°C	13 h 09	68	Strong coverage
May	24.4°C	7°C	36 mm	3.1	10.6°C	14 h 14	84	Strong coverage
June	27.8°C	8.5°C	10 mm	1.1	10.7°C	14 h 50	76	Strong coverage
July	28.5°C	9.8°C	0 mm	0	11.5°C	14 h 36	76	Strong coverage
August	29.2°C	9.6°C	2 mm	0.1	12.4°C	13 h 39	73	Strong coverage
September	29.2°C	8.4°C	4 mm	0.9	12.9°C	12 h 23	71	Strong coverage
October	26.1°C	6.3°C	50 mm	3.4	12.8°C	11 h 08	75	Strong coverage
November	19.8°C	3.7°C	113 mm	7	12.4°C	10 h 02	51	Strong coverage
December	14.7°C	2.1°C	212 mm	10.8	11.8°C	9 h 30	14	Strong coverage

What has changed

Monte Rio runs +1.5°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

+2.9

Feb

+2.0

Mar

+1.2

Apr

+1.6

May

+1.0

Jun

+1.0

Jul

-0.1

Aug

+0.9

Sep

+1.6

Oct

+2.0

Nov

+1.9

Dec

+1.8

May daytime highs, 2011–2025. Last recorded: 26.2°C.

Records at GRATON, 1926–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	28.9°C8 Jan 1962	-7.8°C9 Jan 1937	145 mm4 Jan 1982	599 mm1995 · driest 0 mm in 2026	100
February	31.1°C16 Feb 2016	-8.3°C7 Feb 1989	177 mm4 Feb 1937	631 mm1998 · driest 0 mm in 2026	100
March	33.9°C19 Mar 2026	-3.9°C2 Mar 2011	165 mm9 Mar 1995	518 mm1983 · driest 0 mm in 1988	100
April	36.7°C29 Apr 1981	-3.9°C2 Apr 1936	102 mm27 Apr 1953	262 mm1948 · driest 0 mm in 2024	101
May	39.4°C29 May 1950	-1.7°C18 May 1927	59 mm16 May 1996	153 mm1990 · driest 0 mm in 1970	101
June	42.2°C25 Jun 1976	0.6°C3 Jun 1976	54 mm2 Jun 1967	59 mm2013 · driest 0 mm in 1965	101
July	45.0°C14 Jul 1972	3.3°C6 Jul 2009	31 mm8 Jul 1974	49 mm1974 · driest 0 mm in 2017	100
August	42.8°C14 Aug 2020	1.7°C31 Aug 2007	43 mm28 Aug 1954	69 mm1954 · driest 0 mm in 1956	100
September	46.1°C6 Sep 2022	-2.2°C20 Sep 2012	106 mm18 Sep 1959	107 mm1959 · driest 0 mm in 2006	100
October	41.1°C3 Oct 2012	-5.6°C29 Oct 1971	157 mm25 Oct 2021	441 mm2021 · driest 0 mm in 2003	100
November	33.3°C3 Nov 1929	-6.7°C25 Nov 1986	141 mm22 Nov 1977	433 mm1926 · driest 0 mm in 1933	100
December	27.2°C3 Dec 2011	-10.0°C22 Dec 1990	170 mm19 Dec 1981	641 mm1955 · driest 0 mm in 1989	99

Typical days per month at GRATON, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)
January	<1	0	11	6
February	2	0	7	6
March	4	<1	4	5
April	7	1	2	2
May	14	4	0	1
June	22	10	0	<1
July	26	11	0	0
August	27	12	0	0
September	25	13	0	<1
October	18	8	<1	1
November	5	<1	6	4
December	<1	0	13	6

How often, not how much — every day in GRATON’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%	35%	19%	46%	11.4–16.1°C
February	20%	33%	19%	42%	14.3–19.0°C
March	36%	30%	14%	37%	15.6–21.3°C
April	58%	19%	7%	20%	18.4–23.2°C
May	78%	9%	3%	7%	21.5–26.7°C
June	93%	4%	1%	1%	24.7–29.4°C
July	99%	<1%	<1%	0%	26.6–30.6°C
August	98%	<1%	<1%	<1%	27.0–30.6°C
September	94%	4%	<1%	2%	25.8–30.9°C
October	78%	12%	5%	14%	22.3–27.4°C
November	37%	25%	14%	33%	16.0–21.4°C
December	6%	33%	18%	42%	12.0–15.8°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.

1926Each stripe is one year’s mean temperature against the 96-year average. Warmest: 2020. Coolest: 1948.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 5374275
NOAA station: USC00043578 · GRATON
Station distance: 13.1 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 30 usable years
Daylight: Calculated from latitude 38.47°, mid-month, sunrise to sunset including refraction. Not a station measurement.
Sea temperature: NOAA OISST v2.1 1991–2020 monthly climatology, nearest open water 14 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 GRATON is what differs

Sebastopol→Guerneville→Forestville→Camp Meeker→Graton→Occidental→

Or put two places side by side: Monte Rio vs Sebastopol

Best time to visitMonte Rio.

May

August

May

The whole year,without the guesswork.

Monte Rio runs +1.5°Con the 1961–1990 baseline.

Nearby, measured,and named.

Best time to visit
Monte Rio.

The whole year,
without the guesswork.

Monte Rio runs +1.5°C
on the 1961–1990 baseline.

Nearby, measured,
and named.