S
M
T
W
T
F
S
26
54°
22°
27
49°
32°
28
50°
28°
29
61°
32°
30
57°
24°
1
61°
22°
2
76°
37°
3
73°
39°
4
52°
29°
5
49°
26°
6
53°
29°
7
65°
37°
8
68°
38°
9
67°
40°
10
63°
40°
11
66°
44°
12
68°
44°
13
69°
45°
14
73°
47°
15
72°
47°
16
70°
48°
17
68°
44°
18
71°
50°
19
63°
50°
20
65°
48°
21
62°
42°
22
63°
44°
23
64°
46°
24
65°
45°
25
63°
42°
26
64°
43°
27
64°
44°
28
65°
46°
29
66°
52°
30
65°
47°
31
69°
51°
1
75°
55°
2
76°
54°
3
78°
56°
4
78°
57°
5
79°
57°
6
78°
58°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Gretna
Gretna's May 2026 forecast shows daily high temperatures ranging from 49° to 79°, with overnight lows between 26° and 58°. The average high for May is 67° 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 Gretna. See also: June | July | August.