S
M
T
W
T
F
S
26
63°
41°
27
63°
45°
28
54°
39°
29
59°
38°
30
63°
39°
1
72°
41°
2
59°
48°
3
50°
45°
4
55°
45°
5
52°
39°
6
48°
37°
7
54°
36°
8
59°
43°
9
50°
41°
10
52°
37°
11
46°
37°
12
54°
37°
13
48°
41°
14
50°
36°
15
50°
37°
16
52°
37°
17
55°
43°
18
55°
41°
19
60°
43°
20
53°
48°
21
59°
51°
22
65°
51°
23
62°
50°
24
64°
53°
25
73°
55°
26
69°
51°
27
64°
49°
28
61°
48°
29
59°
47°
30
58°
46°
31
59°
47°
1
52°
43°
2
52°
42°
3
56°
48°
4
54°
49°
5
57°
50°
6
59°
50°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Thornhill
Thornhill's May 2026 forecast shows daily high temperatures ranging from 52° to 73°, with overnight lows between 42° and 55°. The average high for May is 60° with an average low of 48°. 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 Thornhill. See also: June | July | August.
