daylightGMT.m

function[LocalTime]=daylightGMT(cDate,cTimeArray)

%Converts UTC time to local daylight savings time.
%Usage: [LocalTime]=daylightGMT(cDate,cTimeArray)
%
%INPUT:
%   cDate: Date String of format 'mm-dd-yy'.
%   cTimeArray: Numeric array of GMT time values in MATLAB date-number format.
%
%OUTPUT
%   LocalTime:  Numeric Array of adjusted time values in Matlab date-number
%   format.
%
%Modify the parameters listed under 'Variable Declaration' to suit your
%region's DST rules. The default setting is Eastern Time (USA), since we
%made this program in Massachusetts, USA.
%
%PLEASE NOTE: int2strz.m M-File is required for this code to work. Download
%Mr. Carlos Adrian Vargas Aguilera's M-File at:
%
%http://www.mathworks.com/matlabcentral/fileexchange/12973
%
%Place the file int2strz.m in your working directory.
%
%Daylight Savings Time Starts on the Second Sunday in March.
%Daylight Savings Time Ends on the First Sunday in November.
%
%Example:
%
%   timevalues=timescale([50:55])
%
%   timevalues =
%       733774.002268519
%       733774.002314815
%       733774.002361111
%       733774.002407407
%       733774.002453704
%       733774.0025
%
%   localtime=daylightGMT('03-08-09',timevalues)
%
%   localtime =
%       733839.793935185
%       733839.793981481
%       733839.794027778
%       733839.794074074
%       733839.79412037
%       733839.794166667
%
%   datestr(timevalues(1),'HH:MM:SS') --> 00:03:16
%   datestr(localtime(1),'HH:MM:SS') --> 19:03:16

%Created by Shashi Murthy and Andranik Valedi, Beacon Power Corp.

%======Variable Declarations (can be modified to suit local rules)=====

%GMT Adjustment Values - Define Here!
AdjDST=5;               %GMT to Local Time Adjustment Hours (not DST)
AdjNoDST=AdjDST-1;      %GMT to Local Time Adjustment Hours (w/DST)

%DST starts and ends at 2:00 AM
dstHour=2;

%DST starts on the 2nd Sunday of March
dstStartMonth='03';                     %March
dstStartWD=1;                           %Sunday
dstStartWDnum=2;                        %Second Sunday

%DST ends on the 1st Sunday of November
dstEndMonth='11';                       %November
dstEndWD=1;                             %Sunday
dstEndWDnum=1;                          %First Sunday

%---------------------------------------------------------------------

%Gets daylight savings time start date for current year
for i=1:1:(dstStartWDnum*7)                         %Take the maximum number of samples (up to the week of DST starting)
    dstStartDate=datenum([dstStartMonth,'-',int2strz(i,2),'-',cDate(7:8)]);
    sWeekdays(i)=weekday(dstStartDate);
    if sWeekdays(length(sWeekdays))==dstStartWD && length(find(sWeekdays==dstStartWD))==dstStartWDnum
        break
    end
end
dstStartDateTime=dstStartDate+(dstHour/24);         %Official Start Day and Hour of DST

%Gets daylight savings time end date for current year
for i=1:1:(dstEndWDnum*7)           %Take the maximum number of samples (up to the week of DST ending)
    dstEndDate=datenum([dstEndMonth,'-',int2strz(i,2),'-',cDate(7:8)]);
    eWeekdays(i)=weekday(dstEndDate);
    if eWeekdays(length(eWeekdays))==dstEndWD && length(find(eWeekdays==dstEndWD))==dstEndWDnum
        break
    end
end
dstEndDateTime=dstEndDate+(dstHour/24);             %Official End Day and Hour of DST

%===========Append date to input time data array===========
if isnumeric(cTimeArray)==1
    tempTime=floor(cTimeArray(1));
    cDateTimeArray=floor(datenum(cDate))+(cTimeArray-tempTime);
end

%*****************Starts Processing input time array*******************
LocalTime=cDateTimeArray-(AdjDST/24);
for s=1:1:length(cDateTimeArray)
    if LocalTime(s)>=(dstStartDateTime) && LocalTime(s)<(dstEndDateTime)
        LocalTime(s)=LocalTime(s)+(1/24);
    end
end