Possible Clues:

• When the MLS Cup Playoffs begin
• Mo. in which Cornwallis surrendered
• When U.N. Day is celebrated
• Major mo. for campaigners
• Mo. for Mother-in-Law's Day
• National Chili Mo.
• National Arts & Humanities Month: Abbr.
• National Stamp Collecting Mo.
• The 10 in 10/20: Abbr.
• No V afterwards