Summitted it in the Fall, probably mid 80's. Can't imagine going up in the Winter.
Slept on a flat rock just below the summit to stay out of the breeze (which died off after sunset), but we were well-prepared with winter gear (even though early September)...probably in the low 40’s overnight. Marcy alone in late February? No way in hell. (Climbed a number of the 46’ers, but never made it up Marcy...go figure.)