[Edi]

Did you check the glossary tab?

The explanations for zero and negative scale requirements are there and if a scale requirement is present at value zero (as opposed to not being present at all), the event can happen even if tehre are no scales at all. So for example req_scale death(0) means that if you ave 0, 1, 2 or 3 death, it can happen, but if you have growth 1 or higher, it can't.

There is also the pesky little thing that when the events happen, they happen according to the scales and other conditions in the province before hosting and at the beginning of the new turn their effects take place (such as increased misfortune from baleful star).

It sort of has to be that way, unless the turn resolution order places events after everything else. I could do a better analysis if I was home and could check the manual, but alas, I'm at work right now.

Many of the season and cold scale events seemed buggy to me at first, but they are not, and that's in teh code. That's because the dual season (e.g. summer/autumn events like harvests) have a requirement of "cannot happen in spring AND cannot happen in winter", so they can only happen during summer or autumn. Which is six months out of twelve.

That leads to the out of season happening if the trigger conditions are as per the previous turn. Event happens during the turn that is hosted and its effects manifest on the next turn. Therefore it still took place in the appropriate place.

The cold scale events like blizzards don't necessarily have season requirements because you can have cold regions where if you get a cold enough summer, you get snow.

Hope that helps.