because that is the way it runs
Vehicles will often run rough when it is wet if the cap and rotor are not in good condition. Other causes are: condensation in the gas tank, improper carb tuning, needs a tune up
Replace the spark plug wires, that would be my first guess.
The most obvious is hard start, runs rough when wet outside.
A sponge can be both soft when wet and rough when dry.
It is rough and wet
You might check the distributor cap - my 1997 Jetta would run very rough until I got into 2nd gear when the weather was damp or wet. I checked the distributor and not only was one of the connections loose, there was a crack in the cap. After I replaced that...it was perfect in any weather.
cold, wet, hail, rough blizzards earthquakes, sometimes the Atlantic Ocean is so rough is washes away the tools needed for the beach like plastic chairs little tables surf boards etc
wet
the wet seas
Wet Weather - 1922 was released on: USA: 3 September 1922
they got their supplies wet and their selves wet
Wet and Cold