A slightly damp start to the day.. only very low cloud will stop the programme..which isn't that usual. Once the planes have climbed through the 'holes' in the clouds (or just gone straight through them), all you have is blue sky and bright sunshine.. possibly why pilots don't feel so 'under the weather.'

Also the RAF aircraft (technically, owned by a civilian company, hence being on the civilian register) have a complete suite of navigation equipment (including GPS)- so no one ever gets lost!!