Weather in Luzern in September

A good month. September is a solid month to be in Luzern. Highs average 20.4 °C, lows 12 °C, and rain falls on 14 days — nothing in the month is working against you.

September is the highest-scoring month of the twelve. The nearest rival is June, and the month at the other end of the year is January.

Rain on 14 days, 3 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 29.4 °C and the coldest night fell to 2.1 °C, and the wettest single day dropped 48 mm — roughly 48% of the month's rain in one day.

September is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest September on record still delivered 167 mm against 45 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 101 mm average is a reasonable planning figure, not a promise.

Wind is light at 5.3 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 80%, high enough to notice on the warm days without dominating them.

How September sits in the year

The month is on the way down: 3.6 °C cooler than August, with October dropping another 3.5 °C. The first week and the last are not the same trip.

Daylight in September

12.6 hours of daylight, losing 1.7 hours across the month. That is between Luzern's extremes of 15.9 and 8.5 hours, so days are long enough not to constrain the plan.

An inland climate

With no coast nearby, the year swings a fair way — 26.2 °C between the warmest afternoons and the coldest nights, wider than any coastal city at this latitude would manage.

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 Luzern versus nearby

If Luzern is one option among several, the nearby comparison is worth making. Zermatt is the weaker option in September — 5.3 °C cooler, 1 day less rain. Colmar is close enough to be a coin toss — within a degree on temperature, 4 days less rain.

So: September is the answer for Luzern. If it is booked out or priced out, June is the next best thing at 8 points behind, and January is the month to keep off the shortlist.

Every month in Luzern

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