S
M
T
W
T
F
S
26
70°
49°
27
67°
44°
28
56°
39°
29
57°
40°
30
54°
35°
1
53°
31°
2
62°
44°
3
68°
44°
4
73°
39°
5
56°
34°
6
52°
35°
7
56°
35°
8
69°
42°
9
66°
41°
10
65°
45°
11
67°
47°
12
67°
46°
13
69°
44°
14
70°
46°
15
64°
45°
16
65°
47°
17
64°
52°
18
70°
52°
19
72°
53°
20
74°
54°
21
74°
54°
22
67°
47°
23
66°
45°
24
65°
46°
25
64°
49°
26
67°
52°
27
69°
52°
28
68°
49°
29
69°
51°
30
78°
54°
31
69°
50°
1
70°
58°
2
76°
55°
3
70°
53°
4
71°
51°
5
72°
50°
6
72°
50°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Thornton
Thornton's May 2026 forecast shows daily high temperatures ranging from 52° to 78°, with overnight lows between 31° and 58°. The average high for May is 67° with an average low of 47°. 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 Thornton. See also: June | July | August.
