Thats a lot later than I thought.
The reason I asked the original question is that I think the last few seasons have been affected by a lot of wet races. Some people perform better in the dry compared to others in the wet. If theres a lot of wet races then this 'could' dramatically effect on the WDC for that season.
Ironically, if 2002 was a complete dry year its odd that Schumacher (the rainmaster!) won more races that season than any other!
Silverstone was wet.
Do you not remember Raikkonen and Coulthard talking to the chinese restaurant about wet tyres?
I think you have to look back to the 70s, when the seasons start to get shorter than 17-odd races.
It is possible it has never happened since the 50s.