I know the feeling, I commuted daily for several years too, but don’t need to anymore. The weather can be mentally hard to overcome.
My solution? The next few times you are on the train take a video cam with you. When the inevitable 45 minute delay leaves you stationary outside a station in the London suburbs, because somebody thought throwing a a drinks machine on the tracks was funny, remember the frustration, anger, and regret for having not taken the bike. Ditto for the car. Get caught in a 3 hour jam around Oxford on a Sunday and the bike in the rain is a dawdle in comparison.