date_default_timezone_set and Time Zones

["Waynn Lue" <waynnlue@xxxxxxxxx>]

I'm using date_default_timezone_set("America/Los_Angeles") in my code, then
I output it like

date("m/d/y, H:i:s, O", <some unix timestamp>);

But even though it's daylight savings time in Los Angeles, I get output like

[01/31/08, 23:00:00, -0800]

Shouldn't it instead be -0700?  Am I misunderstanding how these timezones
work?

Waynn