What are the significant advantages and disadvantages of applying to and starting a Master's program in the spring semester?

[Pavi]

..

[nugget]

Perhaps making friends. Most programs start in the fall, so if you begin a program later on in the year many students will have already made new friends and it could be a bit more difficult for you to make new friends.

[lyrehc]

A lot of programs will not even consider accepting new students mid-year.  Those that do usually do not offer funding packages because they have extended all aid that they can for the year.  Since programs often tend to offer classes in the fall which are built upon in the spring you may find yourself playing catch up and not understanding concepts which everyone else in the program has grasped.

[fuzzylogician]

Most programs are only set up for fall admissions. If you join in the spring, you will be behind a semester and face the consequences of that, as mentioned above -- being behind on courses, entering an already established cohort, perhaps lacking funding. Logistically, you may have trouble finding a lease that starts mid-year, at least in some cities. If you are joining a program that is set up for spring admissions in addition to fall admissions, then I don't think there is any particular disadvantage, if the spring and fall incoming classes end up having the same opportunities.