Which weather forecast do people actually use for an Elbrus summit day?
Where can I find a weather forecast for Elbrus?
Two sites give usable forecasts for Elbrus at summit height: mountain-forecast.com for Mount Elbrus at 5,642 m, which also has pages for 5,000 m and 4,000 m, and snow-forecast.com for the top of the mountain. For the valley, mountain-forecast.com for Terskol and meteoblue for Mount Elbrus show what the huts and the lifts will get. Use the forecast to pick the day, and your guide's judgement to decide whether to keep going.
The full answer, kept up to date: Where can I find a weather forecast for Elbrus?