this is the answer from Google:
https://www.googleapis.com/calendar/v3/calendars/victoriahighlandgames.com_gufqo1j93tv68t1v0qb840p9s4@group.calendar.google.com/events?key=AIzaSyAssdKVved1mPVY0UJCrx96OUOF9u17AuY&timeMin=2016-05-23T00%3A00%3A00%2B00%3A00&timeMax=2016-05-23T23%3A59%3A59%2B00%3A00&maxResults=2500&singleEvents=true
and those dates are printed on your calendar
In WordPress general settings, you can leave the timezone of your blog – which should be accurate to display your blog post dates right
On each calendar feed, you can choose to base your calendars on the calendar feed timezone, or adjust the calendar events date-time according to your site timezone. In Google, you have two places where you can set a timezone. One is the Google account general timezone (default timezone). Then you can have multiple calendar feeds in Google using this timezone or one set manually.
Set the events on your Google Calendar according to the Google Calendar timezone as you would do normally. Have WordPress use its own timezone (which may or may not match the one of used on your Google Calendar feed), then on the feed settings set ‘use calendar’ for timezone. This, unless you want to convert the calendar feed timezone to WordPress time (for example if your readers want to know the time of an event somewhere else in your blog local time – e.g. a football match, a live webcast, and so on).
About your server – as far as I know it’s best to have the server use UTC and then have your application modify the time – WordPress should do this for you. If you run var_dump( date_default_timezone_get() );
ideally you should get UTC
.
One last thing – if from your site someone clicks a ‘read more’ link from an event to go into Google Calendar app webpage, Google will try to adjust timezones according to the viewer. If you are using ‘use site’ it should pass a variable to adjust the timezone according to that and Google should comply.