S
M
T
W
T
F
S
29
70°
33°
30
79°
52°
31
83°
60°
1
67°
52°
2
79°
62°
3
78°
63°
4
66°
40°
5
57°
40°
6
60°
34°
7
51°
35°
8
63°
47°
9
68°
46°
10
66°
50°
11
70°
53°
12
68°
52°
13
66°
49°
14
64°
44°
15
65°
43°
16
70°
45°
17
59°
43°
18
62°
45°
19
68°
50°
20
71°
52°
21
72°
52°
22
72°
51°
23
73°
53°
24
74°
53°
25
74°
52°
26
70°
43°
27
61°
42°
28
62°
45°
29
64°
46°
30
63°
43°
1
64°
45°
2
65°
47°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
April Weather in Sullivan
Sullivan's April 2026 forecast shows daily high temperatures ranging from 51° to 79°, with overnight lows between 34° and 63°. The average high for April is 67° with an average low of 47°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how April weather will actually feel in Sullivan. See also: May | June | July.