S
M
T
W
T
F
S
26
51°
28°
27
49°
29°
28
55°
27°
29
59°
27°
30
61°
30°
1
66°
28°
2
72°
28°
3
75°
33°
4
71°
43°
5
62°
29°
6
64°
43°
7
76°
39°
8
76°
46°
9
67°
36°
10
71°
41°
11
78°
47°
12
77°
38°
13
75°
42°
14
79°
47°
15
76°
45°
16
74°
44°
17
83°
50°
18
72°
37°
19
61°
34°
20
63°
36°
21
66°
37°
22
73°
46°
23
74°
45°
24
69°
44°
25
73°
44°
26
74°
46°
27
71°
45°
28
64°
42°
29
63°
41°
30
67°
42°
31
73°
46°
1
75°
47°
2
76°
48°
3
77°
49°
4
78°
49°
5
77°
48°
6
78°
50°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Idaho Falls
Idaho Falls's May 2026 forecast shows daily high temperatures ranging from 61° to 83°, with overnight lows between 29° and 50°. The average high for May is 72° with an average low of 43°. 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 Idaho Falls. See also: June | July | August.