The temperatures in Saint Lucia during September are extremely high, between 27°C and hot as 30°C, drinking water regularly is advisable.
You can expect rain for roughly half of the month of September in Saint Lucia. We’re expecting roughly 8 to 15 days of rain, so your rubber boots and umbrella are going to see plenty of use this month if you’re keen on staying dry.
Our weather forecast can give you a great sense of what weather to expect in Saint Lucia in September 2025.
If you’re planning to visit Saint Lucia in the near future, we highly recommend that you review the 14 day weather forecast for Saint Lucia before you arrive.