Weather at a Glance
Season Overview
| Period | Conditions | Crowds | Verdict |
|---|---|---|---|
| Before mid-July | Rock may be heavily iced; conditions unpredictable; hut may not be open | Low | Not recommended for most parties |
| Mid-July to late July | Season opens; rock conditions improving; some icy sections likely remain | Moderate | Viable — verify hut opening date; experienced parties only |
| Late July to mid-August | Best conditions of the year; rock dry; longest daylight | High | Prime season — hut at full capacity; best chance of summit |
| Late August to mid-September | Conditions still good; slightly shorter days; fewer parties | Moderate | Excellent — often less crowded than August peak |
| After mid-September | Early snowfall possible; route icing; conditions deteriorating | Low | Not recommended except for experienced winter alpinists |
Daily Weather Patterns
The Matterhorn’s position at the junction of the Swiss and Italian Alps makes it particularly susceptible to rapidly developing weather. Even on forecast “good” days, afternoon thunderstorms are common from late July onward. The only reliable protection is an early start and a disciplined turnaround time.
Set a turnaround time before you leave the hut — typically no later than 10–11 am — and respect it regardless of how close you feel to the summit. More climbers have been caught by afternoon weather on the upper Matterhorn than on any other single factor. The mountain will be there next year.
Föhn Wind
The Föhn is a warm, dry, powerful southerly wind that funnels through Alpine valleys and over high peaks. On the Matterhorn, Föhn conditions can produce gusts well above 100 km/h on the upper ridges, making any climbing impossible and dramatically increasing the risk of falls and hypothermia. Föhn events are forecast by MeteoSwiss and can arrive with surprising speed. Always check explicitly for Föhn in your pre-climb weather review.
After any precipitation or cloud event, the Matterhorn’s upper rocks can be coated in rime ice — thin, clear ice that is nearly invisible on rock and dramatically increases the difficulty and danger of all sections. This can persist 12–24 hours after the weather event clears. Do not assume clear skies mean dry rock on the upper mountain.
Reading the Forecast
For the Matterhorn, reading the forecast well requires more than a single weather source. The mountain’s exposure means that valley-level forecasts are consistently optimistic about conditions at 4,000+ m.
- MeteoSwiss — the authoritative Swiss national weather service; provides mountain-specific forecasts and Föhn alerts. Use the 3-day and 7-day forecasts.
- Mountain-Forecast.com — elevation-specific forecasts for the Matterhorn summit; wind speed and temperature at 4,500 m are directly usable for planning.
- Hörnligrat Hut Forecast Board — the hut guardian posts and updates a local forecast. This is the most practically useful source the evening before your summit attempt.
- Local Guide Bureau — the Zermatt guide bureau has the most current conditions knowledge; call or visit the day before your planned summit date.
Don’t plan a summit attempt without at least a 3-day high-pressure window confirmed. On the Matterhorn, a 2-day window is rarely sufficient — the first day is typically your approach and hut night, leaving only one summit day. Aim for 3+ clear days so you have flexibility to wait a day at the hut if conditions are marginal on your first summit morning.