<p>I may be wrong, but i believe the difference between Winter/Spring Admit comes from the school’s system. Quarter System- 3 regular terms a year, fall/winter/spring. Semester System- Fall/Spring semester. With regard to the UCs, all the UCs are on the quarter system except Berkeley; so a spring admit would only refer to Berkeley, while a winter admit would refer to rest of the UCs on the quarter system. Both would probably start within the same month ( winter quarter starts in early january, ends in late march/ spring semester starts in late january- ends in early may)</p>