S
M
T
W
T
F
S
26
88°
72°
27
88°
70°
28
86°
74°
29
84°
71°
30
87°
73°
1
87°
72°
2
94°
76°
3
82°
72°
4
82°
71°
5
88°
74°
6
88°
75°
7
85°
76°
8
84°
79°
9
86°
79°
10
86°
80°
11
85°
76°
12
84°
77°
13
85°
78°
14
86°
78°
15
83°
80°
16
83°
78°
17
85°
79°
18
84°
77°
19
81°
78°
20
85°
75°
21
88°
77°
22
87°
78°
23
88°
78°
24
86°
77°
25
85°
78°
26
85°
78°
27
86°
77°
28
85°
77°
29
86°
78°
30
86°
79°
31
87°
78°
1
87°
79°
2
88°
79°
3
87°
78°
4
86°
79°
5
86°
79°
6
85°
78°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Key Biscayne
Key Biscayne's May 2026 forecast shows daily high temperatures ranging from 81° to 88°, with overnight lows between 75° and 80°. The average high for May is 85° with an average low of 78°. 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 Key Biscayne. See also: June | July | August.
