Weather in Groningen in December

The month to avoid. Of the twelve, December is the one to avoid. Highs sit at 5.2 °C and the day is short; this is an indoors-with-excursions month, not an outdoors-all-day one.

December ranks 11 of 12 — near the bottom of Groningen's year. June is the month that works, and the swing between the two is 55 points, which is a different holiday rather than a slightly better one.

This is persistent light rain rather than storms: 15 wet days but only 1 heavy ones. It rarely cancels anything outright, and it rarely fully clears either. A jacket beats an umbrella. Layers, and a genuinely waterproof outer — at 5.2 °C the difference between a good day and a miserable one is entirely down to what you are wearing.

What the averages hide

Averages flatten a month, and this one hides a few things: 11 nights fall below freezing; the day barely swings — 4.1 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest December day reached 13.2 °C and the coldest night fell to -13.2 °C.

December is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest December on record still delivered 137 mm against 27 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 77 mm average is a reasonable planning figure, not a promise.

Wind is light at 15.2 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 94%, which at 5.2 °C means damp rather than muggy — the kind of cold that gets into a coat and stays there.

How December sits in the year

Temperatures hold steady either side: 9 °C in November, 5.2 here, 4.3 in January. Nothing about the timing within the month matters much.

Daylight in December

December sits at the dark end of Groningen's year — 7.6 hours of daylight against 16.9 at midsummer, losing 0.4 hours across the month. Sightseeing days are genuinely shorter, and an itinerary built for summer will not fit.

Sea temperature

The sea sits at about 8.5 °C in December — too cold to swim without a wetsuit. The sea peaks at 18.4 °C in August and bottoms out at 5.3 °C — water lags the air by a month or two, which is why the best swimming often comes after the best weather.

How busy it gets

Quiet. Few other visitors, cheaper rooms, and a real chance some seasonal operators are shut.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

December in Groningen versus nearby

If Groningen is one option among several, the nearby comparison is worth making. Bielefeld is close enough to be a coin toss — within a degree on temperature, 1 day more rain. Rotterdam is close enough to be a coin toss — within a degree on temperature, 1 day more rain.

So: December is a compromise. June is 51 points better and is what Groningen is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in Groningen

See all twelve months in Groningen, or where else to go in December.