S
M
T
W
T
F
S
26
73°
55°
27
73°
54°
28
68°
50°
29
81°
61°
30
75°
57°
1
64°
55°
2
59°
41°
3
70°
46°
4
77°
53°
5
82°
58°
6
83°
65°
7
78°
49°
8
70°
48°
9
75°
55°
10
78°
60°
11
75°
58°
12
73°
55°
13
77°
59°
14
79°
59°
15
78°
56°
16
78°
56°
17
82°
58°
18
83°
61°
19
82°
61°
20
85°
62°
21
84°
61°
22
80°
55°
23
76°
54°
24
77°
56°
25
79°
58°
26
80°
57°
27
78°
56°
28
78°
56°
29
79°
58°
30
81°
60°
31
80°
62°
1
82°
65°
2
83°
64°
3
81°
64°
4
82°
63°
5
84°
65°
6
85°
66°
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 59° to 85°, with overnight lows between 41° and 66°. The average high for May is 79° with an average low of 58°. 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.
