Tromso weather by month
Tromso runs from about -7°C in January to 17°C in August, with November the wettest month at 229 mm.
warmest month
August
17°C
coolest month
January
-7°C
wettest month
November
229 mm
worst air month
January
3 µg/m³
The whole year, month by month.
| Month | Avg temp | Rain | Sun | PM2.5 |
|---|---|---|---|---|
| January | -7°C | 217 mm | 0 h | 3 |
| February | -5°C | 102 mm | 52 h | 3 |
| March | -2°C | 52 mm | 134 h | 2 |
| April | -2°C | 60 mm | 312 h | 3 |
| May | 7°C | 95 mm | 269 h | 2 |
| June | 13°C | 112 mm | 374 h | 2 |
| July | 16°C | 79 mm | 414 h | 3 |
| August | 17°C | 131 mm | 312 h | 3 |
| September | 10°C | 106 mm | 186 h | 3 |
| October | 4°C | 165 mm | 65 h | 2 |
| November | 0°C | 229 mm | 0 h | 2 |
| December | -4°C | 186 mm | 0 h | 3 |
About 2,118 hours of sun a year. Roughly 155 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.