I originally dismissed the talk of weather being an issue; my P1 to P3 birds were all wet weather birds and I can't honestly say I really noticed a difference in the weather conditions. But my P4 bird is a fair weather bird, and wet weather is like trying to race through molasses.

I'm left scratching my head wondering if in my earlier inexperience I hadn't noticed the reverse being true, or whether there is an actual imbalance and fair weather birds are affected more strongly in wet weather, than wet weather birds are affected in fair weather.