This data is technically for Key West, but is close enough.
The actual air temperatures may run 10 degrees above the “average”. The overnight low temperatures in
December and January can approach 50 – 55.
Water temperatures are very stable and usually vary less than a degree or two over the course of a day. Thermoclines are rare but occasionally present in the winter and spring. SUMMERTIME “FEELS LIKE” TEMPERATURES WILL FREQUENTLY APPROACH THE 110º – 115º RANGE. Our humidity is generally above 70%. Use the high temperature from the chart above for the month you are attending PLUS 70% or higher humidity to find the heat index (or feels like temperature) in the chart below.
Heat Index Chart
The Heat Index is the temperature the body feels when heat and humidity are combined. The chart below shows the Heat Index that corresponds to the actual air temperature and relative humidity. This chart is based upon shady, light wind conditions. Exposure to direct sunlight can increase the Heat Index by up to 15 degrees Fahrenheit.
Relative Humidity (%)
40
45
50
55
60
65
70
75
80
85
90
95
100
110
136
-
-
-
-
-
-
-
-
-
-
-
-
108
130
137
-
-
-
-
-
-
-
-
-
-
-
106
124
130
137
-
-
-
-
-
-
-
-
-
-
104
119
124
131
137
-
-
-
-
-
-
-
-
-
102
114
119
124
130
137
-
-
-
-
-
-
-
-
100
109
114
118
124
129
136
-
-
-
-
-
-
-
98
105
109
113
117
123
128
134
-
-
-
-
-
-
96
101
104
108
112
116
121
126
132
-
-
-
-
-
94
97
100
102
106
110
114
119
124
129
135
-
-
-
92
94
96
99
101
105
108
112
116
121
126
131
-
-
90
91
93
95
97
100
103
106
109
113
117
122
127
132
88
88
89
91
93
95
98
100
103
106
110
113
117
121
86
85
87
88
89
91
93
95
97
100
102
105
108
112
84
83
84
85
86
88
89
90
92
94
96
98
100
103
82
81
82
83
84
84
85
86
88
89
90
91
93
95
80
80
80
81
81
82
82
83
84
84
85
86
86
87
With Prolonged Exposure and/or Physical Activity:
Caution:
Fatigue possible
Extreme Caution:
Sunstroke, muscle cramps, and/or heat exhaustion possible
Approximately 400 people die each year from exposure to heat, according to the Centers for Disease Control and Prevention. Our bodies dissipate heat by varying the rate and depth of blood circulation, by losing water through the skin and sweat glands, and as a last resort, by panting, when blood is heated above 98.6 degrees Fahrenheit.
Sweating cools the body through evaporation. However, high relative humidity retards evaporation, robbing the body of its ability to cool itself. When heat gain exceeds the level the body can remove, body temperature begins to rise, and heat-related illnesses and disorders may develop.
If you must be out in the heat:
Limit your outdoor activity to morning and evening hours.
Cut down on exercise. If you must exercise, drink two to four glasses of cool, nonalcoholic fluids each hour. A sports beverage can replace the salt and minerals you lose in sweat.
Warning: If you are on a low-salt diet, talk with your doctor before drinking a sports beverage.
Try to rest often in shady areas.
Protect yourself from the sun by wearing a wide-brimmed hat (also keeps you cooler) and sunglasses and by putting on sunscreen of SPF 15 or higher (the most effective products say “broad spectrum” or “UVA/UVB protection” on their labels).
Provided by the National Weather Service
WHILE WETSUITS ARE GENERALLY NOT REQUIRED, THE FLORIDA SEA BASE RENTS 3mm ONE PIECE, LONG SLEEVED, LONG LEGGED WETSUITS FOR $25 PER WEEK TO SCUBA CREWS IF YOU THINK THE WATER IS TOO COLD. SCUBA CREWS ARE WELCOME TO BRING A WETSUIT FROM HOME IF THEY WANT. WE DO NOT ENCOURAGE WETSUITS FOR THE SAILING CREWS BECAUSE (1) YOUR EXPOSURE TIME WHILE SNORKELING IS RATHER LIMITED (2) THERE IS NO PLACE TO STORE THE WET WETSUITS ABOARD THE VESSELS (3) IF THE WATER IS TOO COLD YOU CAN FISH AND SAIL.
For current weather conditions and forecasts click on the Weather Underground sticker near the top left corner of the page.
