RFC 2616 date/time stamps

Current date:

Tue, 30 Aug 2016 07:15:05 GMT

30 days from now:

Thu, 29 Sep 2016 07:15:05 GMT

365 days from now:

Wed, 30 Aug 2017 07:15:05 GMT

These are they dates you want to use in HTTP headers, such as Last-Modified and Expire, on the Internet.