Rain. Find the best time to go to Saint Lucia. 79 %. Temperature of water and air, precipitation, amount of days with rain and advice on the best time to visit Saint Lucia. The Weather forecast suggests scattered showers, most of the week. The average minimum temperature (usually the minimum temperature is noted during the night) in Saint Lucia in September is 22.0°C (71.6°F). It's enough to keep away both cruise ships and resort visitors. But the weather doesn't keep everyone away. This St Lucia Weather in September overview is based on 12 years of data from the Saint Lucia Meteorological Office (2005 – 2016) as well as my personal observation of St Lucia’s weather. Get the latest coronavirus (COVID-19) updates for St Lucia with current travel advice, statistics and online resources.. Below are the temperatures expected today at popular destinations in St Lucia.Select a destination to compare today's forecast with average weather conditions. September falls in the rainy season with an average precipitation of 252mm (9.9in). The average day light hours per day in St Lucia in September are 12.2 and there are 8.9 hours of sunshine per day on average during September making it a sunny month with few clouds. Humidity. per month. Can anyone give me any insight to the weather. Some brave souls do visit the island's resorts, especially for last-minute vacations if the weather … Average Weather and Climate in September in Saint Lucia, Saint Lucia. Days are usually hot with balmy evenings, so visitors should pack light and cool clothing. St Lucia weather. By Kirk Elliott – BadAss St Lucia Photographer Sharing My Saint Lucia with the World… Introduction. In St. Lucia during September, thunderstorms -- when they occur -- are most likely sometime around 8:00 PM . 31 %. Tourism for St. Lucia drops to the lowest point of the year, according to the Caribbean Tourism Organization. Some brave souls do visit the island's resorts, especially for last-minute vacations if the weather forecast looks good. St Lucia: Seven-day weather forecast. Sun. Get the monthly weather forecast for Saint Lucia Estuary, Kwazulu-Natal, South Africa, including daily high/low, historical averages, to help you plan ahead. Read an overview of the climate. The weather in Saint Lucia can vary slightly from year to year, but these predictions should limit surprises. The average daily maximum is 31 C … St. Lucia weather in September is almost the worst of the year. 28° C. average. average. Some cruise ships also visit the island. September is a hot and slightly rainy time for sunbathing in Gros Islet.September is an excellent month for swimming in Gros Islet with very warm sea temperatures.