Click on a day for an hourly weather forecast
The temperatures in St. John's in September are comfortable with low of 15°C and and high up to 17°C.
You can expect about 3 to 8 days of rain in St. John's during the month of September. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Our weather forecast can give you a great sense of what weather to expect in St. John's in September 2025.
If you’re planning to visit St. John's in the near future, we highly recommend that you review the 14 day weather forecast for St. John's before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 10° / 7° | 10 | 21 | 1 | 146 mm | Bad | St. John's in January |
| February | 9° / 7° | 9 | 19 | 1 | 110 mm | Bad | St. John's in February |
| March | 10° / 7° | 6 | 25 | 0 | 81 mm | Ok | St. John's in March |
| April | 11° / 9° | 5 | 25 | 0 | 60 mm | Ok | St. John's in April |
| May | 13° / 10° | 4 | 28 | 0 | 57 mm | Ok | St. John's in May |
| June | 15° / 13° | 4 | 26 | 0 | 70 mm | Good | St. John's in June |
| July | 17° / 15° | 5 | 26 | 0 | 67 mm | Good | St. John's in July |
| August | 17° / 15° | 5 | 26 | 0 | 91 mm | Good | St. John's in August |
| September | 17° / 15° | 5 | 25 | 0 | 77 mm | Good | St. John's in September |
| October | 15° / 13° | 8 | 23 | 0 | 143 mm | Ok | St. John's in October |
| November | 13° / 11° | 10 | 20 | 0 | 172 mm | Bad | St. John's in November |
| December | 11° / 9° | 10 | 21 | 0 | 165 mm | Bad | St. John's in December |