I'm in Tucson now, but grew up painting in the midwest. It was a little tougher with lacquers, as they tended to "blush" (get cloudy spots) if the temps were cold and damp.

I've never seen any paint manufacturers recommend spraying in temperatures lower than 55 degrees. The key is to use reducer recommended for the temperature of your shop. Thinner coats, and more dry time will help too.