How warm is it in St. Moritz in September?

Daytime highs averaged 12.6 °C, night-time lows 3.1 °C. The highest value of the past 10 years was 21.1 °C (4 Sep 2023), the lowest -7.8 °C (27 Sep 2020).

How often does it rain in St. Moritz in September?

On average there were 15.6 rain days (at least 1 mm) with 120 mm of precipitation in total.

Photo: Travelleronthego49 · CC BY-SA 4.0

🇨🇭 Weather in St. Moritz in September

This is what the weather in St. Moritz (Grisons, Switzerland) was like in September in 2017–2026.

Key facts at a glance

Prevailing weather: Light rain

Avg. daytime high

12.6 °C

9.1 °C – 15.7 °C

Avg. night-time low

3.1 °C

0.4 °C – 5.7 °C

Avg. rain days in period

15.6

52 % of days · ≥ 1.0 mm

Avg. precipitation in period

120 mm

65.0 mm – 178 mm

Avg. sunshine per day

n/a

Sunshine duration is not available from this data source.

Avg. sea temperature

–

No sea nearby – no sea temperature.

Extremes: Highest temperature 21.1 °C (4 Sep 2023) · Lowest temperature -7.8 °C (27 Sep 2020) · Avg. daily peak wind 10 km/h

Weather mix of all days

45Sunny
58Partly cloudy
18Cloudy
89Light rain
67Rain

Summary

On average 12.6 °C during the day and 3.1 °C at night.
On average 15.6 rain days (Rain day = at least 1.0 mm of precipitation) with 120 mm of precipitation in total.
Prevailing: Light rain.
Warmest year: 2026 (avg. 15.7 °C), coolest: 2017 (avg. 9.1 °C).
Wettest year: 2024 (178 mm), driest: 2018 (65.0 mm).
Extremes: 21.1 °C on 4 Sep 2023 and -7.8 °C on 27 Sep 2020.

Overall values from all 10 years. How is this calculated?

Temperatures per year

Average over your travel period

Precipitation & rain days

Year by year

2026
Avg. max15.7°Avg. min4.2°
Rain days
7 Rain days
Precipitation
67.1 mm
Avg. sunshine per day
n/a
Sea temperature
–
Max 20.8 °C · Min -1.5 °C
2025
Avg. max12.2°Avg. min3.0°
Rain days
20 Rain days
Precipitation
151 mm
Avg. cloud cover
67 % cloudy
Sea temperature
–
Max 20.2 °C · Min -1.8 °C
2024
Avg. max10.1°Avg. min1.8°
Rain days
21 Rain days
Precipitation
178 mm
Avg. cloud cover
77 % cloudy
Sea temperature
–
Max 16.9 °C · Min -4.7 °C
2023
Avg. max15.6°Avg. min5.7°
Rain days
11 Rain days
Precipitation
83.3 mm
Avg. cloud cover
48 % cloudy
Sea temperature
–
Max 21.1 °C · Min -2.1 °C
2022
Avg. max10.7°Avg. min1.7°
Rain days
19 Rain days
Precipitation
177 mm
Avg. cloud cover
69 % cloudy
Sea temperature
–
Max 17.8 °C · Min -4.5 °C
2021
Avg. max13.6°Avg. min3.7°
Rain days
14 Rain days
Precipitation
93.2 mm
Avg. cloud cover
61 % cloudy
Sea temperature
–
Max 16.0 °C · Min -1.0 °C
2020
Avg. max12.7°Avg. min3.8°
Rain days
16 Rain days
Precipitation
106 mm
Avg. cloud cover
57 % cloudy
Sea temperature
–
Max 19.1 °C · Min -7.8 °C
2019
Avg. max12.7°Avg. min2.6°
Rain days
10 Rain days
Precipitation
110 mm
Avg. cloud cover
61 % cloudy
Sea temperature
–
Max 18.6 °C · Min -4.5 °C
2018
Avg. max14.0°Avg. min4.0°
Rain days
14 Rain days
Precipitation
65.0 mm
Avg. cloud cover
53 % cloudy
Sea temperature
–
Max 18.5 °C · Min -5.8 °C
2017
Avg. max9.1°Avg. min0.4°
Rain days
24 Rain days
Precipitation
172 mm
Avg. cloud cover
76 % cloudy
Sea temperature
–
Max 15.1 °C · Min -4.7 °C

Frequently asked questions

How warm is it in St. Moritz in September?: Daytime highs averaged 12.6 °C, night-time lows 3.1 °C. The highest value of the past 10 years was 21.1 °C (4 Sep 2023), the lowest -7.8 °C (27 Sep 2020).
How often does it rain in St. Moritz in September?: On average there were 15.6 rain days (at least 1 mm) with 120 mm of precipitation in total.

Check your exact travel dates

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Data sources

Weather data: Data obtained from the NASA Langley Research Center (LaRC) POWER Project funded through the NASA Earth Science/Applied Science Program
Reanalysis (weather model constrained by observations) on a coarse grid of about 50 km. Values represent a large area and can differ from local conditions, especially on islands, coasts and in mountains. No sunshine duration.
Reanalysis (weather model constrained by observations)
Reanalysis values represent a grid cell (approx. 25–50 km) and may differ from local measurements on coasts, islands and in mountains.
Sea temperature: MUR SST data were provided by JPL under support by NASA MEaSUREs program; accessed via NOAA CoastWatch ERDDAP
Daily multi-scale ultra-high resolution (≈ 1 km) analysis of satellite measurements (infrared, microwave) and in-situ data. Represents the foundation temperature below the daily warm surface layer. (Satellite and in-situ analysis)
Place search: Natural Earth (public domain) · GeoNames (CC BY 4.0) / OpenStreetMap (ODbL)