%% Calculate Elapsed Times on DST Shift
% Calculate elapsed times since midnight on a day with a Daylight Saving Time (DST) shift.
% Create a datetime array. Set its TimeZone property to a time zone that observes DST. Set the date to a date when a DST shift occurred.

tz = 'America/New_York';
fmt = 'dd-MMM-yyyy HH:mm:ss z';
t = datetime(2015,3,8,'TimeZone',tz,'Format',fmt) + hours(1:4)

%
% Calculate the elapsed times. The DST shift occurred at 02:00 on March 8, 2015 in this time zone. timeofday accounts for the shift for times at or after 02:00 on this date.

d = timeofday(t)

% Copyright 2015 The MathWorks, Inc.