Spring and Fall in MI are awesome -- alive and gorgeous.
Summer is a swelter, nothing "dry" about that heat. Make sure your AC is in good shape.
Winter sucks. Not necessarily a ton of snow but it never fully melts due to constant overcast and rare sun (a huge difference with, say, Colorado) but it hovers around the freezing point meaning that the snow will melt a little into slush and then refreeze at night. The result is frozen ice slicks and chunks everywhere, or more slush, ice-mud, etc. And it doesn't end till April. Commuting in winter is crap. And it's not helped by being in the far western border of the eastern time zone, so going to work in the frozen ice chunk wasteland mornings may also be in the dark.
A lot of that applies to anyone living in the northeast or upper midwest though. You're gonna miss the Sierras I guarantee it... :/ But money can solve a lot of problems.