A bolt of lightning can appear to come out of the blue on a clear day when in fact a storm can be many miles away and strike on a clear, cloudless day....
Does it need to be stormy looking or can a bolt of lightning happen on a beautiful blue cloudless sky?
If you can hear thunder
You are close enough to be struck by
Lightning
Yes it can, its called heat lightning and is more common in relative dry or low humid areas like deserts but can happen just about anywhere it gets hot and called Indian Rain. It can actually rain under the same conditions with a perfectly blue clear sky