# Daylight savings problem

**URL:** <https://community.particle.io/t/daylight-savings-problem/38424>\
**Category:** Getting Started\
**Created:** [December 29, 2017, 4:59pm UTC](https://community.particle.io/t/daylight-savings-problem/38424 "2017-12-29T16:59:22Z")\
**Posts on this page:** 1\
**Showing post:** 4

<div class="post-metadata">

**Author:** ![ScruffR](https://sea2.discourse-cdn.com/flex026/user_avatar/community.particle.io/scruffr/32/6952_2.png) [@ScruffR](https://community.particle.io/u/ScruffR)\
**Post date:** [December 31, 2017, 4:57pm UTC](https://community.particle.io/t/daylight-savings-problem/38424/4 "2017-12-31T16:57:52Z")

</div>

Hi there, I have not dived into your code but this is what I came up with some time ago

```cpp
bool isDST()
{ // (Central) European Summer Timer calculation (last Sunday in March/October)
  int dayOfMonth = Time.day();
  int month = Time.month();
  int dayOfWeek = Time.weekday() - 1; // make Sunday 0 .. Saturday 6

  if (month >= 4 && month <= 9)
  { // April to September definetly DST
    return true;
  }
  else if (month < 3 || month > 10)
  { // before March or after October is definetly standard time
    return false;
  }

  // March and October need deeper examination
  boolean lastSundayOrAfter = (dayOfMonth - dayOfWeek > 24);
  if (!lastSundayOrAfter)
  { // before switching Sunday
    return (month == 10); // October DST will be true, March not
  }

  if (dayOfWeek)
  { // AFTER the switching Sunday
    return (month == 3); // for March DST is true, for October not
  }

  int secSinceMidnightUTC = Time.now() % 86400;
  boolean dayStartedAs = (month == 10); // DST in October, in March not
  // on switching Sunday we need to consider the time
  if (secSinceMidnightUTC >= 1*3600)
  { // 1:00 UTC (=1:00 GMT/2:00 BST or 2:00 CET/3:00 CEST)
    return !dayStartedAs;
  }

  return dayStartedAs;
}

```

---

_[View the full topic](https://community.particle.io/t/daylight-savings-problem/38424)._