Weather forecasts are based on the analysis of weather data collected by instruments such as satellites, radar, and ground weather stations. This data is then used to make complex mathematical models that predict future weather conditions.
However, it is important to keep in mind that weather is a complex and sometimes unpredictable phenomenon. As such, weather forecasts can be subject to errors and inaccuracies, especially in extreme weather situations or during sudden changes in weather conditions.
Overall, weather forecasts for Montriond are generally reliable, but it is always important to remain vigilant and keep up to date with the latest updates in case of unforeseen changes in weather conditions.