If you look at stats for temperate climates, the chief factor is normally not the winter but the summer. In snowy weather, drivers actually tend to slow down, a

If you look at stats for temperate climates, the chief factor is normally not the winter but the summer. In snowy weather, drivers actually tend to slow down, and even though many go off the road, they are slow crashes with few fatalities. A long, hot summer is deadly though, because it means more miles travelled and hence more accidents. And crashes in the summer tend to be fast, and thus more deadly.