Weather in Zermatt in September

Shoulder season. September sits in between. You will get good days and you will lose some. Highs average 15.1 °C, lows 5.8 °C, and rain falls on 13 days — nothing in the month is working against you.

September ranks 4 of 12 in Zermatt: past the worst of the year but short of August, which is the month to book if the dates are open.

Rain on 13 days, 2 of them heavy. Enough to need a plan B, not enough to need a plan around it. Pack for 15.1 °C days and 5.8 °C nights; the spread matters more here than any single number.

What the averages hide

The averages here are honest — no hidden extremes worth planning around. Across the twenty years measured, the hottest September day reached 25 °C and the coldest night fell to -5.8 °C, and the wettest single day dropped 26 mm — roughly 38% 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 110 mm against 28 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 68 mm average is a reasonable planning figure, not a promise.

Wind is light at 4.8 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 78%, high enough to notice on the warm days without dominating them.

How September sits in the year

The month is on the way down: 3.4 °C cooler than August, with October dropping another 4.2 °C. The first week and the last are not the same trip.

Daylight in September

12.6 hours of daylight, losing 1.6 hours across the month. That is between Zermatt's extremes of 15.7 and 8.7 hours, so days are long enough not to constrain the plan.

An inland climate

With no coast nearby, the year swings a fair way — 28.7 °C between the warmest afternoons and the coldest nights, wider than any coastal city at this latitude would manage. At 1608 m, altitude is doing as much work here as latitude: thinner air means fierce sun by day and heat that leaves the moment it sets.

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 Zermatt versus nearby

If Zermatt is one option among several, the nearby comparison is worth making. Chamonix-Mont-Blanc is a better bet in September — 3.7 °C warmer, the same number of rain days. Luzern is a better bet in September — 5.3 °C warmer, 1 day more rain.

So: September is effectively as good as it gets here — 6 points behind August, which is inside the margin where the weather stops being the deciding factor and price starts being it.

Every month in Zermatt

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