Halfly clouded: Mostly clouded, but sometimes a hole in the cloud deck appears, creating a sunny ray:
You’ll see these rays (made in the same way as the lightning bolts) moving over the landscape. The ray is like the opposite of the thunderstrike, if it hits a hearthling, they look up, take the time to appreciate it and get a happy thought. If it has been halfly clouded or more clouded/rainy for multiple days on end, the happyness buff grows with the amount of days with almost no sunlight.
I love this idea!
Graphics card settings call these god rays, if it matters.