Ask HN: What timezone is HN running on?

I sometimes miss some good articles from the previous day, that were around earlier in the current day.

Is it subjective to the number of new stories being submitted? Is there a daily reset of top stories at some point? If it does, Is it possible to change it to use my timezone?

I am trying to reduce my visits to HN to max once a day. I'd like to come in around the last hour of the day. ;-)

Thanks.