I mean that on a road with a 50mph limit it will be safe to drive 50mph for 99% of the time when raining or windy, not that it's only safe to drive 50mph on a warm, clear day without wind or rain.
Obviously with snow or frozen road it's different.
I hate people that drive 70mph on the motorway and start tapping their brakes if they drive into a bit of rain.
Ah right. I think I agree.. this is where posting 60mph signs instead of NSL signs would be misleading, as many NSL roads aren't safe to do 60 or even 50 along (country lanes)