Which time zone do we use when listing the last modified date in our sitemap?

Hello Everyone

I create the sitemap.xml file for my website by typing it out in a simple text editor following the instructions on the sitemaps.org website. One of the options available is to list the last modified date.

Does anyone know which time zone I should be referring to when listing the last modified date for my website?

My website files are at DreamHost’s US East Coast location. DreamHost’s head office is on the US West Coast. Maybe I should be using international time?

It always seems to be about midnight when I am uploading changes to my website.


my website

Please refer to the Sitemaps Protocol documentation: http://www.sitemaps.org/protocol.html

In short, you can use either time zone, but if you include the time, you must specify a time zone. For instance, for November 5, 1994, 8:15:30 am, US Eastern Standard Time, you would write:

You can also just leave out the time and just specify a date, though. Unless you’re updating a page more than once a day, that should probably be enough:

Thank you Andrew F for your reply.

I have no intention of trying to include the last modified time. It is difficult enough just trying to figure out what day it is. Too often I find myself ready to upload and debug changes to my website in that three hour time gap when it is after midnight on the US east coast (i.e. 1994-11-06) but before midnight on the US west coast (i.e. 1994-11-05).

I have checked the sitemaps.org website a few times and never found anything mentioned about a web hosting company having servers in two different time zones. I guess I will just go with Andrew F’s answer of “you can use either time zone” when picking a date for the line in a website’s sitemap.


I suspect that it doesn’t actually matter. So long as you make some sort of change to the lastMod date for a page when you update it, a search engine can use that as a cue to recrawl the page. They don’t actually need to know exactly what time the page was updated, only that it has changed since they last looked.