Publishing on consecutive calendar days increments your streak.
If you are changing between timezones, you get a grace period to account for the change in timezones. The maximum this period can be is 48 hours (because that's the maximum time change you could have within a 24 hour period).
The general idea is if you publish every calendar day your streak will stay alive. And if you are traveling, you'll get some flexibility in that.
If you feel your streak is incorrect, please message us.