Back in 1980, Daylight saving time (DST) started on April 27th. But calling the
method in System.TimeZoneInfo
class for April 15, 1980 returns true. The following test fails:
- public void DST_Started_On_April_27_1980()
- var ts = new DateTime(1980, 4, 15, 12, 0, 0);
- var isDst = Utils.EasternTimeZone.IsDaylightSavingTime(ts);
Let’s do some sleuthing and get to the bottom of this.