Original name record: MTI Ltd.

A route acquisition process of acquiring a route, a weather risk acquisition process of acquiring a weather risk as three-dimensional information, a first display process of displaying, in plan view, at least each of the route and the weather risk together, and a second display process of displaying the route and the weather risk together on a cross section cut vertically along the route are executed.

The lightning strike risk degree derivation device comprises: an echo intensity derivation unit that derives an altitude distribution of echo intensity in a predetermined altitude range for each of the plurality of regions using observation data acquired from meteorological radar; an air temperature derivation unit that derives an altitude distribution of air temperature in the predetermined altitude range for each of the plurality of regions using observation data acquired from a meteorological observation device; a feature amount derivation unit that derives a feature amount to be used to derive a lightning strike risk degree; and a lightning strike risk degree derivation unit that derives the lightning strike risk degree using the feature amount.