Annual mean 10°C · wettest around May · prevailing wind SW
Warmest
27.5 °C
Coldest
-4.9 °C
Wettest
65%
Windiest
6.8 m/s
Prevailing
SW
5.1 m/s average
When this place is good five ratings · thirty-six ten-day sections · click a cell to read it
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Every reading
bars actual · line feels-like, °Cchance of rain, %wind speed, m/ssky covered, %
The average temperature in Grinnell over the whole year is 10°C. July is the hottest month, with highs of about 27°C; January is the coldest, with lows of about -7°C. Grinnell has no sharply defined rainy season: the chance of rain on a given day runs from 53% in February, the driest month, to 60% in May, the wettest. Winds in Grinnell are highest in April, averaging 5.2 m/s (19 km/h), and lightest in August, at 2.6 m/s (9 km/h). The prevailing wind is from the SW. The clearest skies in Grinnell come in July, when the sky is typically 25% covered; January is the cloudiest month, at 53%.
Month by month Grinnell climate by month: average temperatures year round · click a month to read it
Month
High
Low
Feels like
Chance of rain
Cloud
Wind
Being outside
Sun
Walking
January
-4°C
-7°C
-10°C
53%
53%
4.5 m/s
0
0
1
February
-0°C
-6°C
-7°C
53%
41%
4.6 m/s
1
0
9
March
7°C
1°C
1°C
57%
47%
4.9 m/s
3
0
22
April
13°C
5°C
7°C
59%
43%
5.2 m/s
20
1
46
May
20°C
13°C
17°C
60%
40%
4.1 m/s
56
12
62
June
27°C
19°C
26°C
59%
25%
3.6 m/s
54
50
28
July
27°C
20°C
28°C
59%
25%
2.7 m/s
40
62
13
August
26°C
18°C
27°C
57%
28%
2.6 m/s
52
53
23
September
24°C
15°C
23°C
58%
28%
3.1 m/s
62
37
43
October
16°C
8°C
12°C
56%
37%
3.9 m/s
34
4
57
November
8°C
1°C
2°C
56%
39%
4.4 m/s
7
0
26
December
1°C
-4°C
-5°C
57%
45%
4.3 m/s
0
0
7
High and low are the warmest and coolest of four readings a day — midnight, 6am, noon and 6pm — so a true overnight low can sit a degree or two under them. Chance of rain, cloud and wind are the day’s average; feels-like and the three ratings (each out of 100: Good from 55, Ideal from 80) are read at midday.
Seasons, and the year in short Grinnell weather by season
Year round, Grinnell has days of about -4°C at their warmest in January, its coolest month, and 27°C in July, its warmest; the coolest hours of the day run from -7°C to 20°C through the year, and the average temperature over the year is 10°C around the clock. Rain is most likely around May and least likely around February. Every figure here is a decade of observations blended into one representative year, so it reads as what this date is usually like, not a forecast for one particular day.
Grinnell weather in winterDecember to February
High -1°CLow -6°CRain 54%
Winter in Grinnell has typical daily highs of about -1°C and lows of about -6°C, with a 54% chance of rain on a given day.
Grinnell weather in springMarch to May
High 14°CLow 6°CRain 58%
Spring in Grinnell has typical daily highs of about 14°C and lows of about 6°C, with a 58% chance of rain on a given day.
Grinnell weather in summerJune to August
High 27°CLow 19°CRain 58%
Summer in Grinnell has typical daily highs of about 27°C and lows of about 19°C, with a 58% chance of rain on a given day.
Grinnell weather in autumnSeptember to November
High 16°CLow 8°CRain 57%
Autumn in Grinnell has typical daily highs of about 16°C and lows of about 8°C, with a 57% chance of rain on a given day.
When is the rainy season in Grinnell?
Grinnell has no sharply defined rainy season: the chance of rain on a given day runs from 53% in February, the driest month, to 60% in May, the wettest.
What time of year is Grinnell windiest?
Winds in Grinnell are highest in April, averaging 5.2 m/s (19 km/h), and lightest in August, at 2.6 m/s (9 km/h). The prevailing wind is from the SW.
What is the average temperature in Grinnell year round?
The average temperature in Grinnell over the whole year is 10°C. July is the hottest month, with highs of about 27°C; January is the coldest, with lows of about -7°C.