Explaining the differences in football's schedule this season - Colorado High School Activities Association

Football practice started a week earlier this season. But that’s hardly the only change you’ll notice in the sport in 2018.

Here’s a quick rundown:

The early start, which happened when the football committee opted to move to the NFHS calendar, in effect makes Week 1 of the season Aug. 24. Zero Week does not exist anymore. All teams can begin playing on Aug. 24 — in fact, all Class 5A teams must begin play that week.
… That’s because the 5A playoffs have expanded to 24 teams. The top eight seeds will receive a first-round bye, with seeds Nos. 9-24 playing in the first round of the playoffs.
… As a result, the 5A teams do not have room for a bye week during the regular season. Therefore, they must begin play on Aug. 24 in order to play 10 games.
All other classes — 6-man through 4A — will have a bye week during the regular season.
The initial practice schedule leading up to live contact was lengthened. Helmets only from Aug. 6-8; full uniform (but no player-to-player contact) from Aug. 9-10; full contact permitted on Aug. 11.
All teams can scrimmage on Aug. 16. This also allows non-5A teams to have two scrimmage dates for the first time, if they choose to.
The 5A, 2A, 1A, 8-man and 6-man football playoffs will once again be seeded on the same day, which is Oct. 28 this season. Those playoffs will begin on the weekend of Nov. 1-3.
The 4A and 3A playoffs will be seeded on Nov. 4. Those playoffs begin on Nov. 8-10.
The championship games in 6-man, 8-man, 1A and 2A will be played the same date (Nov. 24). Previously, 6-man’s championship game was a week earlier.

Other notable (non-schedule) changes:

There’s new league alignment this season.
Two-a-day practices are no longer allowed following guidance from the Sports Medicine Advisory Committee. Note that this only applies to on-field activities. Things like weights and film study are still permitted in conjunction with an on-field practice.
The final spot on the 24-team 5A playoff bracket will be selected by the seeding committee.
The 2A and 3A championship games will be hosted at a neutral site. That site has not yet been announced.
The RPI formula that will be used is 30/40/30. More info is available on the RPI FAQ page.