Water Temperature of the Caribbean Sea in St. John, VI
Current Water Temperature
Measurement Time: Friday, September 12, 2025, 3:00 AM AST
Temperature Locations
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Station Name: South of St. John, VI
Station Type: Buoy
Data Source: National Data Buoy Center
Elevation Above Sea Level: 0 feet / 0 meters
Nearest Address:
St. John, VI 00830
GPS Coordinates: 18.249, -64.763
Nearby Water Temperatures
Lameshur Bay, Coral Harbour (St. John), VI (5.4 mi)Long Bay, Charlotte Amalie (St. Thomas), VI (11.9 mi)
Christiansted Harbor, Christiansted (St. Croix), VI (34.9 mi)
Bahía de Sardinas, Culebra, PR (35.6 mi)
Limetree Bay, St. Croix, VI (38.3 mi)
Atlantic Ocean, Vieques, PR (46.0 mi)
Caribbean Sea, Esperanza, PR (47.7 mi)
Atlantic Ocean, San Juan, PR (89.0 mi)
Unnamed Creek, Fort Buchanan, PR (89.5 mi)
Unnamed Creek, Fort Buchanan, PR (89.5 mi)
San Juan Bay, San Juan, PR (89.9 mi)
Las Casas Lake, Fort Buchanan, PR (90.0 mi)
Caribbean Sea, La Parguera, PR (151.2 mi)
Bahía de Mayagüez, Mayagüez, PR (157.5 mi)
Bahía de Aguadilla, Aguadilla, PR (158.1 mi)
Weather for St. John, US Virgin Islands
Current Weather

Humidity: 75%
Feels Like: 110.3°F
Wind: ESE 11.4 mph
Wind Gusts: 15.2 mph
Precipitation: 0 in
Cloud Cover: 50%
Visibility: 9 mi
UV Index: 10.2
Five Day Weather Forecast

Fri
H: 86°F
L: 82°F

Sat
H: 87°F
L: 82°F

Sun
H: 86°F
L: 83°F

Mon
H: 84°F
L: 83°F

Tue
H: 84°F
L: 83°F
Air Quality
Nitrogen Dioxide: 0.37 μg/m3
Sulphur Dioxide: 0.56 μg/m3
Ozone: 48 μg/m3
Astronomical
Sun Transit: 12:15 AM
Sunset: 6:24 PM
Daylight: 12 hrs 17 mins
Moon Transit: 4:05 AM
Moonset: 10:54 AM
Moon Phase: Waning Gibbous
Moon Illumination: 67.4%
Best Times for Fishing or Hunting
Major Periods
3:35 AM - 6:05 AM7:34 PM - 10:04 PM
Minor Periods
9:42 PM - 11:12 PM10:24 AM - 11:54 AM
Action Rating: 3 out of 5
Heat Advisory issued September 12 at 2:14AM AST until September 12 at 4:00PM AST by NWS San Juan PR
Effective: Fri September 12, 2025, 2:14 AM
Expires: Fri September 12, 2025, 4:00 PM
* WHAT...This level of heat affect most individuals sensitive to heat, especially those without effective cooling and/or adequate hydration. Impacts possible in some health system and in heat-sensitive industries. * WHERE...All urban and coastal areas, as well as the eastern interior, Vieques, Culebra in Puerto Rico, and all of the U.S. Virgin Islands. * WHEN...From 10 AM this morning to 4 PM AST this afternoon. * IMPACTS...Hot temperatures and high humidity may cause heat illnesses.
Take extra precautions when outside. Wear lightweight and loose fitting clothing. Try to limit strenuous activities to early morning or evening. Take action when you see symptoms of heat exhaustion and heat stroke. To reduce risk during outdoor work, the Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air conditioned environments. Anyone overcome by heat should be moved to a cool and shaded location. Heat stroke is an emergency! Call 9 1 1.
Heat Advisory issued September 12 at 2:14AM AST until September 12 at 4:00PM AST by NWS San Juan PR
Effective: Fri September 12, 2025, 2:14 AM
Expires: Fri September 12, 2025, 4:00 PM
* WHAT...This level of heat affect most individuals sensitive to heat, especially those without effective cooling and/or adequate hydration. Impacts possible in some health system and in heat-sensitive industries. * WHERE...All urban and coastal areas, as well as the eastern interior, Vieques, Culebra in Puerto Rico, and all of the U.S. Virgin Islands. * WHEN...From 10 AM this morning to 4 PM AST this afternoon. * IMPACTS...Hot temperatures and high humidity may cause heat illnesses.
Take extra precautions when outside. Wear lightweight and loose fitting clothing. Try to limit strenuous activities to early morning or evening. Take action when you see symptoms of heat exhaustion and heat stroke. To reduce risk during outdoor work, the Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air conditioned environments. Anyone overcome by heat should be moved to a cool and shaded location. Heat stroke is an emergency! Call 9 1 1.
Heat Advisory issued September 12 at 2:14AM AST until September 12 at 4:00PM AST by NWS San Juan PR
Effective: Fri September 12, 2025, 2:14 AM
Expires: Fri September 12, 2025, 4:00 PM
* WHAT...This level of heat affect most individuals sensitive to heat, especially those without effective cooling and/or adequate hydration. Impacts possible in some health system and in heat-sensitive industries. * WHERE...All urban and coastal areas, as well as the eastern interior, Vieques, Culebra in Puerto Rico, and all of the U.S. Virgin Islands. * WHEN...From 10 AM this morning to 4 PM AST this afternoon. * IMPACTS...Hot temperatures and high humidity may cause heat illnesses.
Take extra precautions when outside. Wear lightweight and loose fitting clothing. Try to limit strenuous activities to early morning or evening. Take action when you see symptoms of heat exhaustion and heat stroke. To reduce risk during outdoor work, the Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air conditioned environments. Anyone overcome by heat should be moved to a cool and shaded location. Heat stroke is an emergency! Call 9 1 1.
Heat Advisory issued September 12 at 2:14AM AST until September 12 at 4:00PM AST by NWS San Juan PR
Effective: Fri September 12, 2025, 2:14 AM
Expires: Fri September 12, 2025, 4:00 PM
* WHAT...This level of heat affect most individuals sensitive to heat, especially those without effective cooling and/or adequate hydration. Impacts possible in some health system and in heat-sensitive industries. * WHERE...All urban and coastal areas, as well as the eastern interior, Vieques, Culebra in Puerto Rico, and all of the U.S. Virgin Islands. * WHEN...From 10 AM this morning to 4 PM AST this afternoon. * IMPACTS...Hot temperatures and high humidity may cause heat illnesses.
Take extra precautions when outside. Wear lightweight and loose fitting clothing. Try to limit strenuous activities to early morning or evening. Take action when you see symptoms of heat exhaustion and heat stroke. To reduce risk during outdoor work, the Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air conditioned environments. Anyone overcome by heat should be moved to a cool and shaded location. Heat stroke is an emergency! Call 9 1 1.
Heat Advisory issued September 12 at 2:14AM AST until September 12 at 4:00PM AST by NWS San Juan PR
Effective: Fri September 12, 2025, 2:14 AM
Expires: Fri September 12, 2025, 4:00 PM
* WHAT...This level of heat affect most individuals sensitive to heat, especially those without effective cooling and/or adequate hydration. Impacts possible in some health system and in heat-sensitive industries. * WHERE...All urban and coastal areas, as well as the eastern interior, Vieques, Culebra in Puerto Rico, and all of the U.S. Virgin Islands. * WHEN...From 10 AM this morning to 4 PM AST this afternoon. * IMPACTS...Hot temperatures and high humidity may cause heat illnesses.
Take extra precautions when outside. Wear lightweight and loose fitting clothing. Try to limit strenuous activities to early morning or evening. Take action when you see symptoms of heat exhaustion and heat stroke. To reduce risk during outdoor work, the Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air conditioned environments. Anyone overcome by heat should be moved to a cool and shaded location. Heat stroke is an emergency! Call 9 1 1.
Weather Forecast
Average Temperature: 83.2°F
Average Humidity: 80%
Wind: 13.9 mph
UV Index: 2.7
Air Quality
Nitrogen Dioxide: 0.53 μg/m3
Sulphur Dioxide: 0.58 μg/m3
Ozone: 40.6 μg/m3
Astronomical
Sun Transit: 12:15 AM
Sunset: 6:24 PM
Daylight: 12 hrs 17 mins
Moon Transit: 4:05 AM
Moonset: 10:54 AM
Moon Phase: Waning Gibbous
Moon Illumination: 67.4%
Best Times for Fishing or Hunting
Major Periods
3:35 AM - 6:05 AM7:34 PM - 10:04 PM
Minor Periods
9:42 PM - 11:12 PM10:24 AM - 11:54 AM
Action Rating: 3 out of 5
Weather Forecast
Average Temperature: 83.4°F
Average Humidity: 81%
Wind: 19.2 mph
UV Index: 2.7
Air Quality
Nitrogen Dioxide: 0.73 μg/m3
Sulphur Dioxide: 1.04 μg/m3
Ozone: 39.32 μg/m3
Astronomical
Sun Transit: 12:14 AM
Sunset: 6:23 PM
Daylight: 12 hrs 16 mins
Moon Transit: 5:04 AM
Moonset: 12:00 AM
Moon Phase: Waning Gibbous
Moon Illumination: 56.4%
Best Times for Fishing or Hunting
Major Periods
4:34 AM - 7:04 AM8:35 PM - 11:05 PM
Minor Periods
12:00 AM - 12:00 AM11:30 AM - 1:00 PM
Action Rating: 2 out of 5
Weather Forecast
Average Temperature: 83.5°F
Average Humidity: 82%
Wind: 20.4 mph
UV Index: 2.7
Air Quality
Nitrogen Dioxide: 0.81 μg/m3
Sulphur Dioxide: 1.41 μg/m3
Ozone: 40.4 μg/m3
Astronomical
Sun Transit: 12:14 AM
Sunset: 6:22 PM
Daylight: 12 hrs 15 mins
Moon Transit: 6:06 AM
Moonset: 1:04 PM
Moon Phase: Last Quarter
Moon Illumination: 45.1%
Best Times for Fishing or Hunting
Major Periods
5:36 AM - 8:06 AM12:00 AM - 12:00 AM
Minor Periods
12:34 AM - 2:04 PM12:00 AM - 12:00 AM
Action Rating: 2 out of 5
Weather Forecast
Average Temperature: 83.9°F
Average Humidity: 77%
Wind: 20.6 mph
UV Index: 0.2
Air Quality
Nitrogen Dioxide: 0.7 μg/m3
Sulphur Dioxide: 1.25 μg/m3
Ozone: 39.28 μg/m3
Astronomical
Sun Transit: 12:14 AM
Sunset: 6:21 PM
Daylight: 12 hrs 14 mins
Moon Transit: 7:08 AM
Moonset: 2:05 PM
Moon Phase: Last Quarter
Moon Illumination: 34.0%
Best Times for Fishing or Hunting
Major Periods
6:38 AM - 9:08 AM12:00 AM - 12:00 AM
Minor Periods
1:35 PM - 3:05 PM12:00 AM - 12:00 AM
Action Rating: 2 out of 5
Weather Forecast
Average Temperature: 83.7°F
Average Humidity: 77%
Wind: 18.1 mph
UV Index: 6
Air Quality
Nitrogen Dioxide: 0.56 μg/m3
Sulphur Dioxide: 0.4 μg/m3
Ozone: 39 μg/m3
Astronomical
Sun Transit: 12:13 AM
Sunset: 6:20 PM
Daylight: 12 hrs 13 mins
Moon Transit: 8:07 AM
Moonset: 2:58 PM
Moon Phase: Last Quarter
Moon Illumination: 23.8%
Best Times for Fishing or Hunting
Major Periods
7:37 AM - 10:07 AM12:00 AM - 12:00 AM
Minor Periods
2:28 PM - 3:58 PM12:43 AM - 2:13 AM
Action Rating: 2 out of 5