In each claim case, FlightClaimEU will look up the weather records relevant to the airport in the timeframe of the departure/arrival using its comprehensive set of sources. In some specific types of extreme weather conditions, the airline can reject the claim based on extraordinary circumstances. Winds strong enough to constitute a danger to the landing/takeoff operation and significantly decreased visibility qualify as such circumstances, but lightnings for example, do not. You can find more information about this on our flight rights information page.