S
M
T
W
T
F
S
26
45°
20°
27
47°
25°
28
53°
27°
29
38°
16°
30
36°
15°
1
37°
16°
2
41°
20°
3
44°
25°
4
41°
24°
5
40°
19°
6
39°
17°
7
41°
18°
8
41°
21°
9
42°
19°
10
46°
20°
11
46°
21°
12
52°
29°
13
48°
25°
14
44°
23°
15
49°
30°
16
47°
22°
17
42°
21°
18
42°
21°
19
44°
22°
20
45°
24°
21
44°
23°
22
45°
24°
23
45°
28°
24
46°
25°
25
45°
24°
26
44°
24°
27
46°
25°
28
48°
30°
29
58°
36°
30
61°
33°
31
60°
32°
1
55°
28°
2
53°
29°
3
57°
30°
4
54°
26°
5
52°
27°
6
56°
30°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Yellowstone National Park
Yellowstone National Park's May 2026 forecast shows daily high temperatures ranging from 36° to 61°, with overnight lows between 15° and 36°. The average high for May is 47° with an average low of 24°. 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 Yellowstone National Park. See also: June | July | August.