United States · 1991–2020

Best time to visit
Green Valley.

September leads for comfortable weather in Green Valley: typically 26.4°C by day, 12°C at night, with 88 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortSeptember

Typical high26.4°C

Typical low12°C

Rain in September88 mm

Comfort

September

September · May · August

77climate match

Beach

August

August · July · June

75climate match

Outdoors

October

October · April · May

81climate match

The weakest month is January, scoring 5 against September’s 77 — days reach only 0.8°C, 23° 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

50.8° / -8.3°

Feb

54.7° / -5.4°

Mar

2311.2° / -1°

Apr

5118.8° / 5.6°

May

7523.8° / 11.3°

Jun

6628.6° / 16.5°

Jul

5930.1° / 18.2°

Aug

6929.4° / 16.8°

Sep

7726.4° / 12°

Oct

6119.7° / 6.6°

Nov

2311.1° / 0.2°

Dec

52.9° / -6°

Monthly climate evidence for Green Valley — daylight is calculated from latitude, everything else is measured
Month	Day	Night	Rain	Wet days	Daylight	Comfort	Coverage
January	0.8°C	-8.3°C	54 mm	6	9 h 35	5	Good coverage
February	4.7°C	-5.4°C	43 mm	5.2	10 h 36	5	Good coverage
March	11.2°C	-1°C	51 mm	6.7	11 h 49	23	Good coverage
April	18.8°C	5.6°C	98 mm	9.4	13 h 13	51	Good coverage
May	23.8°C	11.3°C	115 mm	9.9	14 h 24	75	Good coverage
June	28.6°C	16.5°C	116 mm	8.7	15 h 02	66	Good coverage
July	30.1°C	18.2°C	117 mm	7.3	14 h 47	59	Good coverage
August	29.4°C	16.8°C	85 mm	6	13 h 46	69	Good coverage
September	26.4°C	12°C	88 mm	6	12 h 25	77	Good coverage
October	19.7°C	6.6°C	80 mm	7.1	11 h 03	61	Good coverage
November	11.1°C	0.2°C	74 mm	6	9 h 53	23	Good coverage
December	2.9°C	-6°C	52 mm	5.5	9 h 18	5	Good coverage

Records at MASON CITY 4SE, 1962–2011
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	21.1°C31 Jan 1989	-31.1°C17 Jan 1977	62 mm8 Jan 2008	102 mm1993 · driest 2 mm in 1986	44
February	23.9°C26 Feb 1996	-27.2°C6 Feb 1982	53 mm22 Feb 1990	102 mm1990 · driest 3 mm in 2004	46
March	30.6°C29 Mar 1986	-22.2°C5 Mar 1978	51 mm13 Mar 1972	208 mm1973 · driest 0 mm in 2001	46
April	32.8°C25 Apr 1986	-9.4°C6 Apr 1982	70 mm30 Apr 1970	186 mm1970 · driest 13 mm in 1971	43
May	35.6°C25 May 1967	-1.7°C3 May 1976	99 mm17 May 1995	300 mm1995 · driest 5 mm in 1964	47
June	39.4°C25 Jun 1988	3.9°C2 Jun 2003	85 mm14 Jun 1990	252 mm1998 · driest 13 mm in 1971	48
July	40.0°C25 Jul 2005	7.2°C27 Jul 1962	104 mm29 Jul 2002	291 mm1992 · driest 5 mm in 1988	48
August	39.4°C20 Aug 1983	4.4°C28 Aug 1986	83 mm6 Aug 1991	189 mm1965 · driest 17 mm in 1992	46
September	37.2°C1 Sep 1984	-2.2°C23 Sep 1995	124 mm14 Sep 1993	264 mm1993 · driest 0 mm in 2004	48
October	34.4°C4 Oct 2006	-7.8°C26 Oct 1962	122 mm4 Oct 1991	223 mm1991 · driest 1 mm in 1964	45
November	27.8°C1 Nov 2000	-20.6°C30 Nov 1964	122 mm5 Nov 2004	240 mm1985 · driest 8 mm in 1999	47
December	22.8°C3 Dec 1970	-30.6°C22 Dec 1989	79 mm3 Dec 1982	185 mm1982 · driest 9 mm in 1976	48

Typical days per month at MASON CITY 4SE, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)	Snow days
January	0	0	26	2	4
February	0	0	23	1	3
March	<1	0	17	2	1
April	4	<1	4	4	<1
May	12	3	<1	3	0
June	23	11	0	4	0
July	26	14	0	3	0
August	26	13	0	3	0
September	17	7	<1	3	0
October	6	1	4	3	<1
November	<1	0	15	2	<1
December	0	0	24	2	3

How often, not how much — every day in MASON CITY 4SE’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%	19%	5%	15%	-3.6–4.9°C
February	1%	20%	5%	16%	-0.6–7.9°C
March	9%	24%	6%	26%	7.8–13.5°C
April	31%	30%	11%	38%	15.5–21.5°C
May	57%	29%	11%	35%	21.3–26.6°C
June	72%	28%	11%	29%	27.3–30.8°C
July	76%	23%	10%	21%	28.9–32.5°C
August	79%	20%	9%	17%	27.4–31.1°C
September	72%	22%	10%	22%	23.9–28.1°C
October	40%	22%	8%	21%	17.4–21.1°C
November	8%	21%	7%	19%	8.0–13.7°C
December	<1%	20%	6%	19%	-1.1–6.5°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.

1963Each stripe is one year’s mean temperature against the 35-year average. Warmest: 1998. Coolest: 2008.2010

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 4894635
NOAA station: USC00115413 · MASON CITY 4SE
Station distance: 27.1 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 16 usable years
Daylight: Calculated from latitude 40.41°, 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 MASON CITY 4SE is what differs

Mason City→Delavan→Greenview→San Jose→Middletown→Easton→

Or put two places side by side: Green Valley vs Mason City

Best time to visitGreen Valley.