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Average St. Thomas Weather in September

St. Thomas weather in September
Average high temperature and rainfall for St. Thomas in September. © 2017 Scott S. Bateman

Hurricanes Irma and Maria in 2017 proved that St. Thomas weather is sometimes a big risk for Caribbean vacationers who go to this U.S. Virgin island in September.

The average St. Thomas weather in September brings total rainfall of five inches and a high temperature of 90 degrees Fahrenheit, according to the U.S. National Weather Service.

But there are exceptions to these norms. Hurricanes Irma and Maria were big ones with heavy rains and pounding high winds that damaged large parts of the island.

St. Thomas is a popular destination for eastern Caribbean cruises. About 2 million people visit the island by cruise every year, according to the Caribbean Tourism Organization. September is the least popular month to visit the island because of the risk of tropical storms and hurricanes.

The annual Caribbean hurricane season begins June 1 and ends Nov. 30. September is the most active month of the season with a historical average of four hurricanes. It is common for two of the hurricanes to become major hurricanes.

St. Thomas Rain in September

The average rainfall of more than five inches in September is nearly the same for the island as October and November, even though September is normally the worst month of the year for the Caribbean as a whole.

By comparison, the island averages less than two inches of rain during the dry season months of January through March. It averages about three inches each month from April through July.

Temperatures in September

This video explains Caribbean weather in September and which islands are the best and worst to visit for weather.

Full-Screen Version | YouTube Caribbean Channel
St. Thomas is one of the warmest islands in the Caribbean even in September as fall approaches.

The average high temperature of 90 degrees Fahrenheit or 32 Celsius maintains a level that begins in July.

The island has an average low temperature of 77 Fahrenheit or 25 Celsius. The lows occur at night.

Swimmers should find comfortable water temperatures that stay between the daily highs and nightly lows. Water temperatures are coolest in the mornings and warmest in the mid to late afternoons.

Island temperatures in September may tempt people to vacation there, but the risk of heavy rain is high. Travel insurance is a wise option.

• St. Thomas weather in January, February, March, April, May, June, July, August, September, October, November, December

Scott S. Bateman is a professional journalist who has traveled widely throughout the Caribbean and the Americas. He is the author of four books about cruising in the Caribbean, Alaska and Mexican Riviera.
August 17, 2021

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