U.S. Virgin Islands · St John
Trunk Bay
Sea
84.2°F
Air
–
UV
–
Bathtub
Above 28°C
More like this
Climate · monthly averages
Sea temperature by month
5-year averages (2021–2025). Min/Max are typical daily lows and highs, not record extremes.
75°F
79°F
82°F
86°F
90°F
93°F
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
MinMin °F
8079.8
7979.0
7979.1
8079.7
8181.0
8282.2
8382.8
8483.6
8584.5
8484.2
8382.8
8181.1
AvgAvg °F
8080.5
8079.7
8079.8
8180.5
8282.2
8383.4
8483.7
8584.5
8585.4
8585.3
8483.8
8282.0
MaxMax °F
8181.3
8080.5
8180.7
8281.8
8483.6
8585.0
8584.8
8585.3
8686.3
8786.6
8584.5
8382.8
Warmest in September (85.4°F). Coldest in February (79.7°F). Comfortable for swimming year-round.
About Trunk Bay
On the north shore of St. John inside Virgin Islands National Park, Trunk Bay holds one of the world's earliest underwater snorkeling trails, with submerged interpretive signs guiding swimmers through a protected reef named for the leatherback turtle. Further east in the same park, Cinnamon Bay opens a long crescent of pale sand, while Maho Bay stays shallow and calm enough for sea turtles to graze on seagrass. Water holds 28 to 29 °C from July through September; Cyril E. King airport on St. Thomas is roughly 45 minutes by ferry and road.