Safety
MWIS
Also called: Mountain Weather Information Service
Definition
The Mountain Weather Information Service is the standard daily mountain weather forecast for Great Britain. MWIS produces region-specific forecasts focused on what matters to walkers: wind speed at altitude, cloud base, freezing level, visibility and precipitation type. Forecasts are issued by 4pm for the next 48 hours.
Etymology & origin
Founded in 2005 by Geoff Monk, a former Met Office forecaster who felt mainstream weather forecasts were too generic for mountain users. MWIS was the first UK service to publish altitude-specific forecasts (summit vs glen floor) and to distinguish between west-coast and east-coast Highland weather patterns. The service is now used by mountain rescue teams, ski centres and guide companies as the standard reference forecast.
Context & usage
MWIS issues seven Scottish regional forecasts: West Highlands, East Highlands, Cairngorms NP and Monadhliath, Skye, Torridon and Fisherfield, North West Highlands, Northern Highlands. Plus equivalent regions for England and Wales. Each forecast is written in plain English by a meteorologist rather than auto-generated — and reads like advice from an experienced hill walker rather than a generic weather report.
The key MWIS conventions: wind speed is given at 900m, the typical Munro summit altitude. Cloud base is given as a height in metres rather than a generic 'overcast'. Freezing level is critical for winter walking — when it's at glen floor, the whole hill is in winter conditions. 'Effect of weather' summarises walking conditions, gear required, and any specific hazards.
MWIS is the consensus daily mountain weather source in Scotland. The Met Office's mountain forecast is the alternative; many walkers cross-reference both. The Norwegian yr.no service is also widely used for its longer-range outlook. For winter days, MWIS is always read alongside the daily SAIS avalanche forecast for the same region.
Related terms
SAIS
The Scottish Avalanche Information Service issues daily avalanche forecasts for six Scottish mountain regions during the winter season (typically mid-December to mid-April). Each daily forecast covers avalanche hazard level (low / moderate / considerable / high / very high), unstable slope aspects, snowpack stability and weather influences.
Winter Munro
A Winter Munro is a Munro climbed in winter conditions — snow on the ground, ice on rocks, and the technical demand for ice axe, crampons and avalanche awareness. Scottish winter conditions typically run November to April, with the peak season December-March. Winter ascents account for the highest-risk Scottish walking outings.
Where to next
Reviewed 2026-05-28