S
M
T
W
T
F
S
26
49°
38°
27
63°
42°
28
64°
45°
29
51°
41°
30
55°
41°
1
50°
39°
2
50°
38°
3
59°
38°
4
68°
47°
5
65°
46°
6
49°
41°
7
56°
40°
8
58°
41°
9
64°
45°
10
57°
43°
11
54°
44°
12
51°
40°
13
63°
46°
14
47°
43°
15
68°
43°
16
72°
53°
17
80°
52°
18
83°
47°
19
81°
59°
20
65°
47°
21
55°
44°
22
57°
47°
23
59°
45°
24
57°
45°
25
72°
45°
26
77°
51°
27
74°
52°
28
67°
51°
29
77°
47°
30
66°
48°
31
74°
48°
1
68°
50°
2
73°
52°
3
74°
55°
4
76°
59°
5
75°
60°
6
69°
56°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in St. Catharines
St. Catharines's May 2026 forecast shows daily high temperatures ranging from 66° to 77°, with overnight lows between 47° and 60°. The average high for May is 72° with an average low of 53°. 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 St. Catharines. See also: June | July | August.
