Only happens to stations located in east and central time zones. I’ve never seen it before since I’m in the Pacific time zone.
The tick mark times and tide tables times appear to be correct. Only the graphed line function is offset by one hour for the entire month.
Doesn’t seem to happen in any year except 2020, which I believe is due to the time change happening on November 1st for this year.
(The data set for a station is provided in monthly chunks).
So the tide data is correct, but the line graphing function has a bug.
(The data set for a station is provided in monthly chunks).