Saint John Weather in September
September in Saint John brings high temperatures, with highs of 30°C (86°F) and nights dropping to 27°C (81°F). It's the rainiest month of the year, so come prepared with waterproof gear.
Rainfall in Saint John in September
With the most rainfall occurring this month, it's practical to keep an umbrella handy for sudden downpours. Historically, approximately 19 days this month are expected to have rain, averaging 145 mm (5.7 in). Expect frequent rainfall this month, and not just light drizzle. When it rains, it tends to come down hard.
Temperature in Saint John in September
Saint John in September gets highs of 30°C (86°F) during the day and drops to 27°C (81°F) at night. Overall, the month follows a fairly predictable daily temperature pattern. With lows of 27°C (81°F), it stays warm throughout the night. A cold shower before going to sleep is one of the easiest ways to cool down before bed.If you prefer dry days with pleasant temperatures, September may not be the ideal month to visit Saint John. Our weather planner can help you explore destinations with more pleasant weather conditions.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit US Virgin Islands, check out our Saint John's climate page.
Saint John Temperature in September
Min Temperature
27°C (81°F)
Max Temperature
30°C (86°F)
Chance of Rain
62%
Precipitation
145 mm (5.7 in)
Rainy days
19 days
Daily Historical Temperatures
45-year average (1976-2025)
Based on our historical records, temperatures in Saint John typically stay consistent throughout September, with daily highs averaging around 30°C (86°F). Nights are warm, with lows around 26°C (79°F).
Average temperatures in September
Daily Historical Precipitation
45-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in September
Historical weather for Saint John in September
Browse day-by-day weather records for Saint John spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Saint John historical weather extremes in September
Based on weather observations in Saint John between 1999 and 2025, these are the recorded extremes during September.
- On September 7, 2007, temperatures climbed to 39°C (102°F), marking the warmest September day on record.
- The coldest September day was on September 15, 2004, with a maximum of 26°C (79°F).
- Saint John registered its coldest September night on September 5, 2009, with temperatures dropping to 22°C (72°F).
Best Places in US Virgin Islands in September
Find out more about the weather in US Virgin Islands and which places have the best travel conditions in this month. See all of US Virgin Islands in September →
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What to Wear in Saint John in September
Warm weather calls for comfortable, breathable clothing in September. Cotton t-shirts, shorts, light dresses, and sandals are perfect. You might still want a light layer for evenings or air-conditioned places (for example buses). High rain levels are expected, so pack waterproof gear and an umbrella or poncho.What To Do in Saint John in September
We rated the following activities from 1 (least suitable) to 10 (best) to do.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit US Virgin Islands, check out our Saint John's climate page.
See the full Saint John climate overview or explore weather in US Virgin Islands.
