That's a very good question.
I think part of it is that living in LA, you have it drummed into you that there is no weather. There is, though. Perhaps because it's often subtle, there's more reward for instrumenting it.
Part of it is I have a marvelous southwest view and can watch the weather change. Quantifying it connects me to the universe.
Part of it is probably my childhood - I mean, any jackass can put a thermometer on his wall. But you throw up a cup anemometer and suddenly you're no longer fucking around. Those groovy weathervanes were always cool to me.
Part of it is likely the altruism - I enjoy knowing that the weather for two or three zip codes in one of the biggest cities in the world comes from me.
And part of it is connecting the immutable natural world to the ephemeral digital one and knowing that part of that fabric is being woven by me.
Does that make sense?