You don't have to be in a thunderstorm to get hit by lightning. A lot of precipitation that paints green contains enough static to create a discharge if your aircraft happens to be oppositly charged, especially at or above the freezing level. Frequently "p-static" can be heard over the radios in this situation.

Commonly you'll recieve the same charge as the area around you, but occasionally, you'll transit to another area that has an opposite charge and generate the discharge before the two oppositely charged areas do it by themselves.

Lightning can be frequently found well outside areas of moderate of heavy precip when in TRW environments.