Trondheim records about 892mm of rain across roughly 128 wet days a year, which is a 35% chance on an average day. October is the wettest month at 88mm (10% of the annual total) and April the driest at 48mm. Local rain type: snow mix. Trondheim gets moderate rain year-round with snow from November through March. The medieval Bakklandet district offers atmospheric shelter.
Chance of rain on an average day: 35%
Rainfall climatology for Trondheim. The live hour-by-hour answer for today loads at the top of this page from Open-Meteo and refreshes through the day — the figures below describe a typical year, not today.
Last updated: · Live forecast data refreshes hourly.
| Annual rainfall | 892mm |
| Rain days per year | 128 |
| Odds on an average day | 35% |
| Wettest month | October — 88mm over 14 days |
| Driest month | April — 48mm over 7 days |
| Rain type | snow mix |
| Best dry window | May and June offer the driest weather with long Nordic summer daylight. |
| Worst rain window | October through December brings dark, wet conditions. |
October delivers 83% more rain than April (88mm vs 48mm). That gap is the difference between planning around showers and ignoring them.
No single month holds more than 10% of the annual total, so rain in Trondheim is spread through the year — there is no season you can rely on being dry.
Trondheim rain typically comes as discrete showers, so a compact umbrella and a flexible plan are usually enough.
Rain falls on about 14 days in October against 7 in April — the frequency swing matters more for planning than the millimetre totals.
Climate normals. Use them to judge whether today's live forecast at the top of the page is typical or unusual for the season.
| Month | Rainfall | Rain days | Chance on a given day | Highs |
|---|---|---|---|---|
| January | 78mm | 12 | 40% | 1°C |
| February | 62mm | 10 | 33% | 1°C |
| March | 54mm | 8 | 27% | 3°C |
| April | 48mm | 7 | 23% | 7°C |
| May | 52mm | 8 | 27% | 12°C |
| June | 62mm | 10 | 33% | 16°C |
| July | 72mm | 11 | 37% | 18°C |
| August | 82mm | 13 | 43% | 18°C |
| September | 80mm | 12 | 40% | 16°C |
| October | 88mm | 14 | 47% | 12°C |
| November | 72mm | 11 | 37% | 7°C |
| December | 82mm | 13 | 43% | 3°C |
Rain probability is the chance that at least 0.2mm falls at your location — not how long it rains. For Trondheim we combine the hourly probability curve, expected volume in millimetres, and the city's own rainfall record into a single umbrella verdict.
| Factor | Weight | What it measures |
|---|---|---|
| Hourly probability | 40% | Peak and sustained chance of measurable rain across the next 24 hours. |
| Expected volume | 30% | Total millimetres, which separates a passing shower from a genuine soaking. |
| Timing & duration | 20% | When rain starts, when it eases, and the longest continuous dry window. |
| Local rain type | 10% | Drizzle, brief showers, thunderstorms or monsoon — each needs different gear. |
Live hourly values come from Open-Meteo and refresh through the day. Monthly rainfall figures are climate normals, so they describe a typical year rather than a forecast.
Trondheim records rain on roughly 128 days a year — about a 35% chance on any given day — totalling around 892mm.
October, with about 88mm over 14 rain days. That is 10% of the entire year's rainfall in a single month.
April is the driest month at 48mm across roughly 7 days. May and June offer the driest weather with long Nordic summer daylight.
Trondheim gets moderate rain year-round with snow from November through March. The medieval Bakklandet district offers atmospheric shelter.
No. Probability is the chance that at least 0.2mm of rain falls at your location at some point in the period. Check the expected millimetres alongside it: 40% with 0.4mm is a passing shower, 40% with 12mm is a soaking.