We’re close enough to the big day(s) now that we can start getting a reasonably accurate picture of what All Hallow’s Eve might look like weather-wise (every day closer will refine the forecast though, so this is not set in stone by any means).
According to Accuweather, the biggest trouble spots will be in the Pacific Northwest, the Great Lakes region, the Ohio Valley, and parts of the South Central United States. In particular, thunderstorms could be possible across the Arklatex into Mississippi. That needs to be watched the closest as severe weather is not at all uncommon in the South during Autumn.
Meanwhile, the vast majority of the country should be seeing nice weather for Halloween activities with mild conditions settling in across the Mid-Atlantic, cool conditions in New England, and pleasant weather currently expected for the Mid-West and desert Southwest.