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Precipitation
Temperature
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Temperature Unit Selection
°Celsius
°Fahrenheit
Monthly Historical Averages
Harriston, ON
Mother's Day weekend forecast
Content continues below
May
Average Temperature
High
18°
Feels 18
Low
7°
Feels 5
Average Precipitation
10 Days
Rain amount
46.3mm
Snow amount
0.1cm
Content continues below
Daily Historical Averages
May 2026
S
M
T
W
T
F
S
1
2
3
4
5
6
7
8
9
16°
10
11°
11
8°
12
10°
13
10°
14
13°
15
15°
16
15°
17
17°
18
19°
19
17°
20
18°
21
18°
22
18°
23
18°
24
25
26
27
28
29
30
31
Forecast
Saturday, May 9, 2026
Day
16°
Feels 15
Wind
34 km/h S
Gust
51 km/h
Humidity
48%
P.O.P
90%
Rain
~5 mm
Night
1°
Feels -2
Wind
32 km/h W
Gust
48 km/h
Humidity
93%
P.O.P
60%
Rain
<1 mm
Historical Averages
May 9
High
Feels
Low
Feels
Precip Frequency
Total Daylight
Humidity
Historical Averages are based on data recorded from 2000 onwards.