INSTRUMENT / SEA TEMPERATURE
Trunk Bay Water Temperature
Updated Mon 13:51 (America/St_Thomas)
US Virgin Islands · Forecast updated Nov 9, 2026, 13:51 UTC
Current Sea Temperature
29.5°C
85.1°F
Very warm water
Valid Nov 9, 2026, 13:51 (America/St_Thomas). Source: stored Open-Meteo marine forecast. Temperature is not a safety rating or snorkel score.
Versus this month's average
0.5°C above
The typical November average is 29.0°C (84.2°F) from the historical baseline.
Recent trend
Holding fairly steady
Seven-day average: 29.5°C, versus 29.7°C in the prior seven days.
What to wear
Very warm water
Swimwear is usually enough; a rash guard adds sun protection.
Cold tolerance varies. Wind, session length, sunshine, and exertion also affect comfort; temperature alone does not describe sea conditions or replace the snorkel forecast.
Typical Sea Temperature Over the Year
In the historical baseline for Trunk Bay, typical monthly averages range from about 26.5°C (79.7°F) in February to 30.1°C (86.2°F) in September.
Over the past 30 days, the average sea temperature in Trunk Bay has been 29.6°C.
Historical baseline (full year)
Northern Hemisphere. Summer is generally June–August; winter is December–February.
Typical monthly sea-surface temperature near Trunk Bay, calculated from hourly observations for 2022–2025. This is not this site's forecast archive.
| Month | Typical range | Average |
|---|---|---|
| January | 26.5–27.5°C | 27.1°C / 80.8°F |
| February | 26.0–27.0°C | 26.5°C / 79.7°F |
| March | 26.3–27.2°C | 26.9°C / 80.4°F |
| April | 26.9–27.7°C | 27.3°C / 81.1°F |
| May | 28.0–28.8°C | 28.3°C / 82.9°F |
| June | 28.2–29.7°C | 29.0°C / 84.2°F |
| July | 28.6–29.6°C | 29.2°C / 84.6°F |
| August | 29.3–29.7°C | 29.5°C / 85.1°F |
| September | 29.8–30.3°C | 30.1°C / 86.2°F |
| October | 29.6–30.4°C | 30.0°C / 86.0°F |
| November | 28.7–29.2°C | 29.0°C / 84.2°F |
| December | 27.1–27.8°C | 27.6°C / 81.7°F |
Source: Open-Meteo Marine API, MeteoFrance sea-surface temperature dataset. Nearest sea grid cell (18.38, -64.79). Each month is the mean of yearly monthly means; the range is the lowest and highest of those yearly monthly means. Open-Meteo methodology.
Water temperature by month
Each month uses the 2022–2025 baseline. The range is the lowest and highest yearly monthly mean, not an hourly extreme.
Trunk Bay in January
Typical January water temperature near Trunk Bay is 27.1°C (80.8°F), with yearly monthly means from 26.5–27.5°C.
Swimming and snorkeling: warm water. Most people are comfortable in swimwear or a light rash guard.
Adjacent months: December 27.6°C · February 26.5°C.
Explore Trunk Bay sea temperature in January, including swim comfort and month comparisons →
Trunk Bay in February
Typical February water temperature near Trunk Bay is 26.5°C (79.7°F), with yearly monthly means from 26.0–27.0°C.
Swimming and snorkeling: warm water. Most people are comfortable in swimwear or a light rash guard.
Adjacent months: January 27.1°C · March 26.9°C.
Explore Trunk Bay sea temperature in February, including swim comfort and month comparisons →
Trunk Bay in March
Typical March water temperature near Trunk Bay is 26.9°C (80.4°F), with yearly monthly means from 26.3–27.2°C.
Swimming and snorkeling: warm water. Most people are comfortable in swimwear or a light rash guard.
Adjacent months: February 26.5°C · April 27.3°C.
Explore Trunk Bay sea temperature in March, including swim comfort and month comparisons →
Trunk Bay in April
Typical April water temperature near Trunk Bay is 27.3°C (81.1°F), with yearly monthly means from 26.9–27.7°C.
Swimming and snorkeling: warm water. Most people are comfortable in swimwear or a light rash guard.
Adjacent months: March 26.9°C · May 28.3°C.
Explore Trunk Bay sea temperature in April, including swim comfort and month comparisons →
Trunk Bay in May
Typical May water temperature near Trunk Bay is 28.3°C (82.9°F), with yearly monthly means from 28.0–28.8°C.
Swimming and snorkeling: very warm water. Swimwear is usually enough; a rash guard adds sun protection.
Adjacent months: April 27.3°C · June 29.0°C.
Explore Trunk Bay sea temperature in May, including swim comfort and month comparisons →
Trunk Bay in June
Typical June water temperature near Trunk Bay is 29.0°C (84.2°F), with yearly monthly means from 28.2–29.7°C.
Swimming and snorkeling: very warm water. Swimwear is usually enough; a rash guard adds sun protection.
Adjacent months: May 28.3°C · July 29.2°C.
Explore Trunk Bay sea temperature in June, including swim comfort and month comparisons →
Trunk Bay in July
Typical July water temperature near Trunk Bay is 29.2°C (84.6°F), with yearly monthly means from 28.6–29.6°C.
Swimming and snorkeling: very warm water. Swimwear is usually enough; a rash guard adds sun protection.
Adjacent months: June 29.0°C · August 29.5°C.
Explore Trunk Bay sea temperature in July, including swim comfort and month comparisons →
Trunk Bay in August
Typical August water temperature near Trunk Bay is 29.5°C (85.1°F), with yearly monthly means from 29.3–29.7°C.
Swimming and snorkeling: very warm water. Swimwear is usually enough; a rash guard adds sun protection.
Adjacent months: July 29.2°C · September 30.1°C.
Explore Trunk Bay sea temperature in August, including swim comfort and month comparisons →
Trunk Bay in September
Typical September water temperature near Trunk Bay is 30.1°C (86.2°F), with yearly monthly means from 29.8–30.3°C.
Swimming and snorkeling: very warm water. Swimwear is usually enough; a rash guard adds sun protection.
Adjacent months: August 29.5°C · October 30.0°C.
Explore Trunk Bay sea temperature in September, including swim comfort and month comparisons →
Trunk Bay in October
Typical October water temperature near Trunk Bay is 30.0°C (86.0°F), with yearly monthly means from 29.6–30.4°C.
Swimming and snorkeling: very warm water. Swimwear is usually enough; a rash guard adds sun protection.
Adjacent months: September 30.1°C · November 29.0°C.
Explore Trunk Bay sea temperature in October, including swim comfort and month comparisons →
Trunk Bay in November
Typical November water temperature near Trunk Bay is 29.0°C (84.2°F), with yearly monthly means from 28.7–29.2°C.
Swimming and snorkeling: very warm water. Swimwear is usually enough; a rash guard adds sun protection.
Adjacent months: October 30.0°C · December 27.6°C.
Explore Trunk Bay sea temperature in November, including swim comfort and month comparisons →
Trunk Bay in December
Typical December water temperature near Trunk Bay is 27.6°C (81.7°F), with yearly monthly means from 27.1–27.8°C.
Swimming and snorkeling: warm water. Most people are comfortable in swimwear or a light rash guard.
Adjacent months: November 29.0°C · January 27.1°C.
Explore Trunk Bay sea temperature in December, including swim comfort and month comparisons →
Forecast archive (growing)
These values come from hourly forecasts SnorkelForecast has stored. They cover only months with records and do not replace the historical baseline.
| Month | Min | Average | Max |
|---|---|---|---|
| June | 27.8°C / 82.0°F | 28.2°C / 82.8°F | 28.7°C / 83.7°F |
| July | 28.3°C / 82.9°F | 28.6°C / 83.5°F | 29.0°C / 84.2°F |
| August | 28.7°C / 83.7°F | 29.2°C / 84.5°F | 29.8°C / 85.6°F |
| September | 29.2°C / 84.6°F | 29.6°C / 85.3°F | 30.0°C / 86.0°F |
| October | 29.3°C / 84.7°F | 29.7°C / 85.4°F | 30.0°C / 86.0°F |
| November | 29.3°C / 84.7°F | 29.5°C / 85.2°F | 30.0°C / 86.0°F |
Partial coverage: 6 calendar months with records. Profile calculated from 3886 hourly forecast records across 6 monthly periods. This is a growing archive, not a long-term climate normal.
About the water at Trunk Bay
Virgin Islands National Park bay with a marked underwater snorkeling trail.
- Area
- St. John
Trunk Bay Water Temperature: Common Questions
What is the water temperature in Trunk Bay today?
The current sea surface temperature near Trunk Bay is 29.5°C (85.1°F). Over the last 30 days, the average has been 29.6°C.
When is the water warmest in Trunk Bay?
The water is typically warmest in September, at around 30.1°C (86.2°F) in the 2022–2025 historical baseline.
When is the water coldest in Trunk Bay?
The water is typically coldest in February, at around 26.5°C (79.7°F) in the same historical baseline.
Can you swim in Trunk Bay today?
At 29.5°C, the water is usually comfortable for swimming and snorkeling.
Full Snorkeling Forecast
See how today's sea temperature, wave height, wind, and tides combine into a detailed snorkeling score for Trunk Bay.
View Snorkel Forecast →