My favorites sites to check the weather before flights:
Weatherspark is my favourite and very cool website with very advance weather models, diagarams and history base of weather in dashboard mode.Long term history of climate in specific areas. Many options allows you to grab weather forecast in nearest areas around. You deicide about range of area.
and popular Czech
Windguru covering also whole globe
For Finland I’m using http://ennuste.ilmailuliitto.fi/