Reading mountain weather means more than checking a sun or rain icon. Before setting off, consider the forecast at your route’s altitude, hour-by-hour changes, wind and the risk of hazardous weather together: these are what really shape an outing.
Choose a forecast for your mountain range
The weather in the valley does not necessarily reflect conditions on a pass or ridge. Check a mountain weather forecast, then compare the altitudes along your route with those covered by the forecast. Météo-France Montagne brings together forecasts by mountain range, snow conditions and, in season, avalanche risk information.
Read the changing picture, not a snapshot
Check the hour-by-hour forecast for when you will be at your highest point, then for your descent. Stronger winds, worsening visibility or showers forecast for late in the day may justify an earlier start, a lower route or a shorter outing. Start by studying your route and its escape options.
Turn the forecast into a decision
- Set a time by which you want to have left higher ground.
- Choose a lower alternative if wind, rain or fog are likely.
- Decide in advance which warning sign will trigger your turn-back decision.
A forecast is not a guarantee: once you are out, the sky, wind and terrain remain your most direct sources of information about actual conditions. To put this plan together, see our approach to route planning, weather and a plan B.
FAQ
When should you check the weather?
The day before to prepare, then in the morning to confirm. If your outing is long or takes you to different altitudes, keep an eye on conditions before setting off and as you walk.
Does a risk of showers mean your hike is a no-go?
Not necessarily. The terrain, timing, wind, exposure and your safety margin determine whether the route is still suitable or needs to be simplified.
Make a check that leads to a decision
The day before, note your maximum altitude, departure window, when you will be most exposed and straightforward alternatives. In the morning, do not simply look for confirmation of your plan: look for information that could change it. If wind, poor visibility or the risk of showers are expected earlier, adjust your objective before leaving the car park.
On an outing lasting several hours, reassess whenever there is a clear change: reaching a ridge, clouds building, wind strengthening or falling behind your planned schedule. This routine helps you avoid treating the weather as information you only check once.
Compare the forecast with what you observe
At the start, note the wind direction, how quickly the clouds are changing and how cold or warm it feels. If these signs differ significantly from the forecast you based your plan on, do not try to work out which is right: choose a simpler option. Useful weather information is information that helps you act on the ground.