High humidity and cold air potentially causes moisture to condensate on ignition wires. Seen this happen all the time when I used to live in Vancouver, BC. This condensation would then cause either a no start condition or miss-fire.
Personally I never warm up the Subaru warming up really is a waste of fuel and does not help "warm" everything up at the same time. Just start it and go, usually within 1/2 mile to 1 mile the engine coolant is already approaching 60 C. Sitting their letting it idle for 20-30 mins, you'd be lucky if it even comes close to 60C, it might stay around 40C. While you're sitting their letting it idle, that transmission is not warming up at all. If you have good 5W-XX oil, its thin enough to lubricate the engine well enough to not warrant idling.....
Personally I never warm up the Subaru warming up really is a waste of fuel and does not help "warm" everything up at the same time. Just start it and go, usually within 1/2 mile to 1 mile the engine coolant is already approaching 60 C. Sitting their letting it idle for 20-30 mins, you'd be lucky if it even comes close to 60C, it might stay around 40C. While you're sitting their letting it idle, that transmission is not warming up at all. If you have good 5W-XX oil, its thin enough to lubricate the engine well enough to not warrant idling.....
