I believe this common "old wives tale" is mostly "mental", because if you think about it, when the weather is rainy and gloomy, our mental state mirrors it, making us "feel" the same way, same as when it is sunny, our moods lift and we are happier....there is little or no evidence that weather conditions can affect us "physically".
I had a damp cloth. The weather was rather damp today.
Trees cause damp .trees underneath
There are two: 'mild' and 'damp'.
Change the wires, rotor and cap.
Damp.
The weather is hot and damp
it neutralizes it
Cracked distributor cap or bad spark plug wires/connections.
They get soggy in damp weather.
damp/moist
It can be cold and damp
warm and damp