Here are things I have tried: logged out and logged back in. Filled out my location (town, state, zip) information. Removed the Activity tile from the board and then put it back. The display remains utterly convinced that I am still on Pacific time. This is annoying.
Further things tried: changed the time zone to even more different time zones (Tel Aviv, etc.). Changed the clock to 24 hour clock. Changed the start of the week to Monday. YES I am hitting save after each of these changes, switching back to the dashboard and looking at the activity tile. Which remains relentlessly convinced I became active at 4:30 a.m. (I got up because my son wanted me to help him out at 7:30 a.m. my time, hence, 4:30 a.m. Pacific), went all sedentary again until 6 a.m. (because it's Saturday, so A. didn't get up until kinda late and I took advantage of that fact). Etc.
ETA: Still not fixing it. Grrr. I did, on the bright side, go in and turn off a whole lot of notifications, so that's not nothing.
Final update on this topic, because I am Really Done with it: It turns out that FitBit handles the time change by ... presenting me with a three hour gap. Really. And it further turns out that R. noticed this back in December, when we flew west and experienced a time zone change and it _double counted_ three hours worth of steps.
Clearly, FitBit is not storing data on the device in GMT/UMT, but rather local time, and then, obvs, the transition isn't being handled right either, because, duh, if you don't handle everything under the hood in UMT/GMT you are going to get it wrong because that's just how it works.
If FitBit were app and device only, I might shrug and go, okay. But they require a computer to set things up, which makes me just want to cry. There is no excuse for getting time and date stuff wrong in 2015.
In other news, A. is now circling while holding her iPod Touch and watching her steps count up. "Look it, if I walk faster I get more steps!" Oy.