Weather in Groningen in September

A good month. September is a solid month to be in Groningen. Highs average 18.8 °C, lows 10.8 °C, and rain falls on 12 days — nothing in the month is working against you.

September ranks 2 of 12 in Groningen. Only June scores clearly higher, and the difference is small enough to be settled by price rather than weather.

Rain on 12 days, 1 of them heavy. Enough to need a plan B, not enough to need a plan around it. Nothing specialised needed — this is the month you pack for the trip rather than for the weather.

What the averages hide

Averages flatten a month, and this one hides a few things: it never really gets hot: not one day in an average September reaches 30 °C. Across the twenty years measured, the hottest September day reached 29.2 °C and the coldest night fell to 4.1 °C, and the wettest single day dropped 25 mm — roughly 40% of the month's rain in one day.

September is moderately variable: 16 mm in the driest year against 152 mm in the wettest, around an average of 63 mm. Roughly two Septembers in three land near that average, and the third does something else entirely.

Wind is light at 12.3 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 82%, high enough to notice on the warm days without dominating them.

How September sits in the year

The month is on the way down: 3.2 °C cooler than August, with October dropping another 4.6 °C. The first week and the last are not the same trip.

Daylight in September

12.8 hours of daylight, losing 2.1 hours across the month. That is between Groningen's extremes of 16.9 and 7.6 hours, so days are long enough not to constrain the plan.

Sea temperature

The sea sits at about 17.3 °C in September — cold — a quick dip rather than a swim, and a wetsuit if you are in for longer. This is the warmest the water gets all year.

How busy it gets

Peak season. Expect the highest prices of the year and to be booking well ahead.

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

September 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 less rain. Rotterdam is close enough to be a coin toss — within a degree on temperature, 1 day more rain.

So: September is effectively as good as it gets here — 2 points behind June, which is inside the margin where the weather stops being the deciding factor and price starts being it.

Every month in Groningen

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