Board Thread:The Quarters - Q & A/@comment-60.242.176.209-20150805011843/@comment-203.9.185.254-20150805022111

Habitica does use the time and timezone set on your PC(s) and mobile device(s); that is certain.

If you use it on two or more devices that don't have EXACTLY the same time and timezone, you will get problems, although typically not the one you describe.

What is your custom day start? It's available from Settings -> Site. If it's late in the day, you will get the behaviour you describe, because as far as Habitica is concerned, it is still Tuesday until your PC/phone's time is after your custom day start time.

Are your Tuesday Dailies set to be due only on Tuesday? Please check that, even if you're certain they are.