The five major Democratic candidates in the May 15 mayoral primary are to debate three times in the next four nights. Here are the details:

Today: 7 p.m. on 6ABC with host Jim Gardner. The debate, in the main auditorium of Drexel University, is sponsored by 6ABC, Drexel, the Philadelphia Tribune, and the League of Women Voters.

Sunday: 8 p.m. on WHYY TV12 and WHYY-FM (90.9) with host Marty Moss-Coane. The debate, at the WHYY Technology Center, is sponsored by The Next Mayor, a joint effort of the Committee of Seventy, the Philadelphia Daily News, and WHYY.

Monday: 7 p.m. on NBC10 with host Chris Matthews. The debate, at the National Constitution Center, is sponsored by the Philadelphia Tribune, WHYY and NBC10.