I cycled a reasonable distance to work (about 25km a day) here in sunny Scotland and rain wasn't really a problem, or snow - but cycling in really high winds isn't a great idea.

Edit: To explain - I was cycling on a that was on top of an embankment and a strong gust of wind unbalanced me at a bad moment when a lorry was passing - I actually hit the lorry with my shoulder and was knocked back upright again. This was all quite exciting at the time.