Time Machine has been removed from the app due to many complaints of its accuracy. Its usefulness was very limited as weather forecasts cannot be predicted that far in advance (and they never included precipitation) and historical data wasn't stored so these were also inaccurate. Furthermore, far future forecasts aren't given by all providers so looking up the time machine forecast for today or a time in the next week didn't always agree with the forecast from the chosen provider, causing a lot of confusion. There were a lot of problems with it and even though sufficient warnings were given, people still complained. Therefore it has been removed as it is more of a gimmick than a useful tool.