Monthly Historical AveragesGrantham, ON
Average Temperature
High
24°
Feels 24
Low
15°
Feels 14
Average Precipitation
12 Days
87.7mm
0cm
Content continues below
Daily Historical Averages
S
M
T
W
T
F
S
ForecastTuesday, June 9, 2026
Day
29°Feels 36
Wind
15 km/h S
Gust
23 km/h
Humidity
55%
P.O.P
40%
Rain
<1 mm
Night
20°Feels 22
Wind
20 km/h S
Gust
30 km/h
Humidity
100%
P.O.P
80%
Rain
2-4 mm
Historical AveragesJun 9
High
Feels
Low
Feels
Precip Frequency
Total Daylight
Humidity