S
M
T
W
T
F
S
26
62°
37°
27
64°
35°
28
62°
40°
29
66°
42°
30
66°
42°
1
65°
42°
2
67°
43°
3
68°
44°
4
69°
44°
5
68°
43°
6
68°
44°
7
67°
41°
8
67°
42°
9
60°
40°
10
68°
46°
11
65°
46°
12
70°
45°
13
65°
45°
14
71°
48°
15
71°
49°
16
72°
49°
17
72°
50°
18
73°
37°
19
64°
37°
20
66°
38°
21
65°
42°
22
66°
48°
23
69°
49°
24
64°
51°
25
72°
50°
26
77°
47°
27
73°
53°
28
75°
51°
29
67°
46°
30
72°
46°
31
75°
51°
1
79°
52°
2
80°
54°
3
80°
47°
4
77°
43°
5
69°
42°
6
73°
52°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Thief River Falls
Thief River Falls's May 2026 forecast shows daily high temperatures ranging from 60° to 80°, with overnight lows between 35° and 54°. The average high for May is 69° with an average low of 45°. 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 Thief River Falls. See also: June | July | August.