S
M
T
W
T
F
S
26
35°
26°
27
51°
19°
28
57°
28°
29
60°
28°
30
66°
33°
1
73°
34°
2
69°
37°
3
76°
36°
4
54°
38°
5
51°
25°
6
74°
23°
7
69°
47°
8
76°
42°
9
66°
45°
10
80°
40°
11
75°
45°
12
77°
38°
13
89°
45°
14
63°
42°
15
64°
38°
16
56°
40°
17
41°
34°
18
53°
30°
19
61°
43°
20
56°
37°
21
61°
39°
22
68°
44°
23
78°
48°
24
80°
50°
25
78°
43°
26
64°
45°
27
73°
47°
28
73°
47°
29
71°
43°
30
68°
44°
31
70°
47°
1
80°
54°
2
67°
44°
3
72°
49°
4
73°
49°
5
69°
48°
6
64°
47°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Great Falls
Great Falls's May 2026 forecast shows daily high temperatures ranging from 56° to 80°, with overnight lows between 37° and 54°. The average high for May is 70° with an average low of 46°. 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 Great Falls. See also: June | July | August.
