95 s10 2.2l 165k miles. Starts hard, then runs rough on mornings after a rain shower, or when it is moist/dew out. After approx 5-10 minutes of rough running/driving, it runs fine. Spark plugs and wires were changed approx 2-3 years/40k miles ago. What should I look for?

When its running fine spray down the wires/cap/rotor/coil with soapy water and see if it starts to run ruff again. If the ignition system is leaking you will likly hear the snapping sound of electricity arcing to ground. If its dark out sometimes you can see it. Personally I just start grabbing wires until I feel the leak, I would recommend it but over the years I've been hit so many times it doesn't bother me any more and there is no question if they are leaking! :)

I would say that the cap/rotor would be worth focusing on.