IIRC, there are some modules that give you a buff or more turns or whatever depending on your race.
Or maybe it is possible to write some special events only during a type of weather? Like, kid lost in the woods during heavy rainshowers, feed your aligniment...
Though thinking about it a bit more, I would be hard-pressed to think of a number of realistic-sounding events that would give some bonus, and having only events in which you can get a penalty/die or avoid undesireable effects are, at least for me, boring and well... Irritating.
Plus, it would be kind of a turn-off. I mean, here are the ninjas, fighting against chimeras, werewolfs, conversing with forest spirits etc, and now... You fight against... a flood.
Maybe such events would be along the lines of being in a terrible storm, and seeing a spirit of the storm - Tempest, controlled by an evil ninja. Then you can fight him, try to run from it, or try to release him. If you succeed in releasing him, he thanks you and gives you a bonus.
You know, something along the lines of mystical and fantasy. I don't think that events such as finding shelter during a heavy rain or blizzard, or running out of the forest during thunderstorm would be very interesting for gameplay.
