"Misfire" in the wet.....

Have recently experienced what appears to be a coil pack type "misfire" during the wet weather.
Today apparently the car has driven faultlessly, and of course it's been dry all day.
I did squirt every visible electrical connection under the bonnet with WD40 but I suspect that it is the wet which was the cause.
I have had coil packs go before and I suspect that this might be the start of at least one failing again, but I'd prefer not to go down that track unless I have to.....
Any suggestions guys??
Thanks
Paul
Verdoandjean