Halloween is two months from today!  I can't recommend that you start stockpiling candy quite yet. (We both know it would never see the autumnal equinox, let alone Halloween.)  There are some things you can do, however.

• Start thinking about costumes.  If you plan to make costumes, you'll want to have patterns and materials in hand by late September, earlier if you need to make more than two.  The terror of Halloween should not be caused by needing to sew 5 cosumes in 2 hours.
• Decide if you will host a Halloween party.  Halloween is a Saturday this year, so more people may decide to entertain.  If you will host a party, it's not too soon to think about guest list, menu, and decor.  At least, you may want to do some web searching for ideas.
• If you decorate, use the time you put your summer things in storage to check on your decorations from past years.  See what's usable, what's trash, and what needs repairs.  If you'll be making things, decide on your projects and gather materials.  Use spare blocks of time to do what you can ahead of time.