As far as I know all the M3Ps are only summer P-zeros these days (previously summer Michelin PS4). I did see one post about a MYP coming with all seasons, but haven’t seen a second post about it. So yeah, all summers.
Some say 40, some say 45. Most say don’t even store them in those temps, let alone operate them that cold. In addition to the tread pattern being suboptimal, the far larger issue is that the rubber turns hard, and not in a nice linear, predictable way, but rather in a less predictable and more dangerous way.
Imagine backing out of your garage with warm, okay sticky tires, only to have them gradually cool down and get harder as you motor along the highway and then when you exit, they are hard and slick and not at all like they were on the on-ramp.
Air temp and tire temp are loosely related but independent. That why in car races you sometimes see cars behind a yellow flag darting back and forth—they’re trying to create lateral friction loads to keep the tires hot and sticky.