Maintaining Streaks, Timezones & Nightly Re-evaluation
With streaks, you have until the end of today to maintain a streak. The end of day is based on the timezone on your user profile. Every night at 00:00 (based on the timezone on your user profile), all habit streaks are re-evaluated.
If switching timezones, there shouldn't be an issue, but if something does look weird, to recalculate the streak considering new timezone, you can: