why does lightning and thunder seem to always happen at night
Thunderstorms can happen at any time of the day. The severity of the thunderstorms has no correlation with the time of day, but it does with your region. The closer you are to the equator the more likely you are to witness thunderstorms because of the relatively high humidity in the equatorial region. Perhaps you witnessing more at night is just a coincidence.
Well if you are religious like me you could pray to Jesus and trust in him that he will keep you safe. Or if you are more technical you could picture a lightning bolt in the sky and how cool it would look in the clouds. Or if you weren't so technical you could count the seconds there are between a lighting bolt and the thunder. Well hope one of those helps. You could also try just relaxing and thinking of something else. And don't worry, the lightning won't hurt you or burn down your house. You can forget all those stories that you've watched on The Weather Channel, those things only happend to like a dozen people out of the rest of the world, thats why they are on tv. If it was common than it probably would be a late night special.
because thats when theres enough moisture in the clouds to create thunder and lightning from the friction