Detect BST in php - php

Question

I am building a booking system in php that offers session times for people to book outdoor activities.
In the summer months, there is an extra session available at the end of the day, because of Daylight Savings, there is an extra hour in the evenings.
Year Clocks go forward Clocks go back
2014 30 March 26 October
2015 29 March 25 October
2016 27 March 30 October
2017 27 March 30 October
2018 25 March 28 October
I am using this...
$todaysDate = strtotime(date("Y-m-d"));
$bstBegin = strtotime("2015-03-29");
$bstEnd = strtotime("2015-10-25");
if($todaysDate > $bstBegin && $todaysDate > $bstEnd)
{
echo "<option value="evening">Evening Session</option>";
}
I only need to show this extra option in the select list between these dates. Is this something I will need to set manually from year to year, or is there a PHP date variable that knows the days the clocks change?

Answer 1

$today = strtotime(date("Y-m-d"));
if (date('I', $today)) {
echo "We're in BST!";
} else {
echo "We're not in BST!";
}
or use the DateTime object equivalent, which maintains details of all the transition dates globally

Answer 2

I work normally with the DateTime functions and like it very much. You have a lot of possibilities to modify a date.
But in your case you can concat the actual year to your string.
$todaysDate = strtotime(date("Y-m-d"));
$bstBegin = strtotime(date('Y')."-03-29");
$bstEnd = strtotime(date('Y')."-10-25");
I hope i have understood your problem correctly.

Answer 3

I have found this online very good ref : https://gist.github.com/aromig/56376f76d4fb653ba83e
public function is_BST() {
$theTime = time();
$tz = new DateTimeZone('Europe/London');
$transition = $tz->getTransitions($theTime, $theTime);
$abbr = $transition[0]['abbr'];
return $abbr == 'BST' ? true : false; }