St. John's weather by month
St. John's runs from about -3°C in January to 18°C in August, with November the wettest month at 289 mm.
warmest month
August
18°C
coolest month
January
-3°C
wettest month
November
289 mm
worst air month
August
16 µg/m³
The whole year, month by month.
| Month | Avg temp | Rain | Sun | PM2.5 |
|---|---|---|---|---|
| January | -3°C | 81 mm | 115 h | 3 |
| February | -2°C | 160 mm | 115 h | 3 |
| March | 0°C | 185 mm | 158 h | 4 |
| April | 3°C | 158 mm | 142 h | 5 |
| May | 6°C | 96 mm | 163 h | 6 |
| June | 13°C | 182 mm | 218 h | 6 |
| July | 18°C | 91 mm | 280 h | 8 |
| August | 18°C | 110 mm | 260 h | 16 |
| September | 14°C | 57 mm | 181 h | 5 |
| October | 9°C | 121 mm | 184 h | 5 |
| November | 6°C | 289 mm | 55 h | 3 |
| December | 1°C | 133 mm | 89 h | 3 |
About 1,960 hours of sun a year. Roughly 167 rainy days a year.
These are long-run climate normals, not a forecast. A given year can sit well outside them. PM2.5 is a global model: near the coast it counts sea salt as fine particulate and reads high against ground stations, sometimes by a factor of two. Use the shape of the year, not the absolute number.
where these numbers come from
- · Temperature, rainfall and sunshine: ECMWF ERA5 reanalysis climate normals via Open-Meteo (CC BY 4.0), fetched once and stored.
- · PM2.5: Copernicus CAMS reanalysis, monthly means. Modelled, not station readings; near coasts CAMS counts sea salt as PM2.5 and reads high.
Last reviewed 2026-05-24. Full method, licences and the list of sources we rejected are on the methodology page.