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
81°
74°
5
82°
75°
6
84°
78°
7
85°
77°
8
84°
76°
9
83°
79°
10
84°
77°
11
83°
76°
12
84°
75°
13
84°
77°
14
85°
77°
15
84°
76°
16
83°
78°
17
84°
81°
18
84°
77°
19
85°
77°
20
85°
78°
21
86°
78°
22
86°
76°
23
87°
76°
24
85°
78°
25
84°
78°
26
85°
78°
27
88°
79°
28
86°
78°
29
85°
77°
30
85°
78°
31
84°
77°
1
85°
78°
2
86°
78°
3
86°
78°
4
87°
77°
5
87°
78°
6
86°
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 74° and 81°. The average high for May is 85° with an average low of 77°. 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.
