If you live in the UK you might have a surprise waiting in store for you if you use Zend_Date for the time part only. For a while I even thought this was a bug, however digging deeper has shown that actually it’s Zend_Date that is right, in a way at least.

When setting a time before 1972 – this is 1970 and 1971 the time part will not be shifted in the UK locale as DST was only introduced in 1972!

This means if you are only calculating times and need the appropriate time adjustment you will need to set a date as no date part in Zend_Date means 1st Jan 1970.