S
M
T
W
T
F
S
26
54°
37°
27
69°
38°
28
70°
46°
29
48°
39°
30
48°
35°
1
45°
37°
2
46°
34°
3
64°
35°
4
74°
46°
5
65°
45°
6
46°
38°
7
53°
41°
8
59°
41°
9
66°
45°
10
52°
40°
11
49°
37°
12
52°
42°
13
60°
45°
14
58°
46°
15
68°
47°
16
64°
48°
17
60°
46°
18
64°
47°
19
65°
57°
20
61°
44°
21
60°
45°
22
61°
46°
23
62°
48°
24
63°
49°
25
64°
49°
26
65°
50°
27
64°
47°
28
68°
54°
29
70°
55°
30
73°
57°
31
74°
57°
1
74°
54°
2
68°
57°
3
74°
58°
4
76°
60°
5
76°
60°
6
75°
59°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Sarnia
Sarnia's May 2026 forecast shows daily high temperatures ranging from 46° to 76°, with overnight lows between 37° and 60°. The average high for May is 64° with an average low of 49°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how May weather will actually feel in Sarnia. See also: June | July | August.
