PHP datetime difference in seconds missing one hour [duplicate]

Question

Possible Duplicate:
One hour difference, but only for some dates

Why:

strtotime('2012-11-01 00:00:00') - strtotime('2012-10-01 00:00:00')

is returning:

2674800

When the right value is:

2678400

is missing one hour.

Answer 1

Because your locale (as defined by date.timezone in php.ini) probably experienced a time change sometime in October, due to daylight savings time.