Hi Malcolm,
As Rich mentioned Seattle is your closest track (3 hour drive), followed by a new track Ridge Motorsportspark (4 hours), Portland (5 hours), and Oregon Raceway (7 hours). All these have frequent track days if that's what you're looking for. Wheel to wheel racing occurs at all these tracks too plus a 'so so' road course at Mission Raceway close to Vancouver itself. Coming from U.K. the weather should be familiar.