When I explore with my one wolf blitz, she does 22 damage without any weather effects. When i PvP battle with her, she does 17 damage. I'm not using a damage increase item or anything during explore so why are the damages different?

It could depend on the time of day. Day/Night affects faction damage.

I thought that during the day lightseeker got a boost (and visa versa) instead of darkseekers getting reduced damage

Actually, that is true. I've noticed that with my wolves as well. I've noticed that one of them does 30 damage in Explore, but in PvP only 22 or 23.

So I spent time working with my wolf blitz. She now does 32 damage in explore without any weather affects. I PvP battle with her aand she does 27. All I can thing is that weight doesn't matter in PvP? She's a heavy weight, but is her weight useless in PvP battles?

With blitz its still the same, but now with my wolf poki its weird. In pvp he does 23 damage, but exploring is only 12.5