WordPress has always had a difficult relationship with timezones. Until recently, you couldn’t specify named timezone regions (only UTC offsets), and even today you can’t expect to use some of PHP’s built-in datetime functions without coming up against timezone issues. To overcome some issues, I’ve created a version of PHP’s Date() and StrToTime() functions that correctly handles local times in WordPress.

The first function – wp_strtotime() – accepts one input parameter, and utilises the DateTime and DateTimeZone classes, along with the configured local timezone in WordPress, to return the date as Unix timestamp.

Here’s the function:

 

The second function – wp_date_localised() – accepts two input parameters (the format and timestamp strings), and returns the timestamp converted to the specified format in your local timezone.

Here’s the function:

 

You can use this code in your own themes or functions (it’s probably best to preface the function names with your own namespace). Simply input a timestamp in any of the usual PHP valid formats, and you get a Unix Timestamp back. To convert the other way, input the format & Unix Timestamp to get a local, formatted string back.

This code attempts to use the WordPress options ‘timezone_string‘ and ‘gmt_offset’ when parsing the provided timestamp.

DateTime code is difficult. While researching this issue I found a lot of mis-information and frankly dangerous information. This code attempts to fix those misconceptions about DateTime in WordPress. If you find any unaccounted edge cases, or have discovered a better way to deal with this issue, please feel free to make a comment below or on Github.

I’ve used this code myself in some bespoke client plugins, as well as my new MetaRadio WordPress Plugin. It’s proven a handy way to accept localised datetime input and convert it to Unix time where it can be handled appropriately.