It appears to have this stuff down to the second. For example:
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/New_York -4:56:02 - LMT 1883 Nov 18 12:03:58
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Chicago -5:50:36 - LMT 1883 Nov 18 12:09:24
Although this won't really be accurate, because it doesn't have every single city. The New_York zone covers the whole eastern time zone even though all the cities in that zone would have been different before 1883. But it is in the database, even if it's not quite right for anything outside of the named cities.
It appears to have this stuff down to the second. For example:
Although this won't really be accurate, because it doesn't have every single city. The New_York zone covers the whole eastern time zone even though all the cities in that zone would have been different before 1883. But it is in the database, even if it's not quite right for anything outside of the named cities.