How to get the day of year in a batch file - windows

Question

How can I get the day of year from the current date in a Windows batch file?
I have tried
SET /A dayofyear=(%Date:~0,2%*30.5)+%Date:~3,2%
But it does not work with leap years, and it is always off by a few days. I would not like to use any third-party executables.

Answer 1

If you want the Julian Day Number, you may use the method posted in my accepted answer given at previous link. However, the "day of year" is just a number between 1 and 365 (366 for leap years). The Batch file below correctly calculate it:
#echo off
setlocal EnableDelayedExpansion
set /A i=0, sum=0
for %%a in (31 28 31 30 31 30 31 31 30 31 30 31) do (
set /A i+=1
set /A accum[!i!]=sum, sum+=%%a
)
set /A month=1%Date:~0,2%-100, day=1%Date:~3,2%-100, yearMOD4=%Date:~6,4% %% 4
set /A dayOfYear=!accum[%month%]!+day
if %yearMOD4% equ 0 if %month% gtr 2 set /A dayOfYear+=1
echo %dayOfYear%
Note: This relies on the date format MM/DD/YYYY.
EDIT 2020/08/10: Better method added
I modified the method so it now uses wmic to get the date. The new method is also shorten, but no simpler! ;):
#echo off
setlocal
set "daysPerMonth=0 31 28 31 30 31 30 31 31 30 31 30"
for /F "tokens=1-3" %%a in ('wmic Path Win32_LocalTime Get Day^,Month^,Year') do (
set /A "dayOfYear=%%a, month=%%b, leap=!(%%c%%4)*(((month-3)>>31)+1)" 2>NUL
)
set /A "i=1, dayOfYear+=%daysPerMonth: =+(((month-(i+=1))>>31)+1)*%+leap"
echo %dayOfYear%

Answer 2

#Aacini's answer has got two weak points (although it suffices for many applications, and it is a great approach after all!):
the retrieved system date relies on format MM/DD/YYYY, but %Date% is locale-dependent;
the calculation does not fully comply with the definition of leap years (see this article);
The following is a revised version of #Aacini's batch script (described within explanatory remarks):
#echo off
setlocal EnableDelayedExpansion
set /A i=0, sum=0
rem accumulate day-offsets for every month in %accum[1...12]%
for %%a in (31 28 31 30 31 30 31 31 30 31 30 31) do (
set /A i+=1
set /A accum[!i!]=sum, sum+=%%a
)
rem check for availability of alternative date value given via (1st) command line argument,
rem just for convenient batch testing
if "%1"=="" (
rem WMIC retrieves current system date/time in standardised format;
rem parse its output by FOR /F, then store it in %CurrDate%
for /F "tokens=2 delims==" %%D in ('wmic OS GET LocalDateTime /VALUE ^| find "="') do (
set CurrDate=%%D
)
) else (
rem apply date value from command line in YYYYMMDD format (not checked for validity)
set CurrDate=%1
)
rem extract %month% and %day%;
set /A month=1%CurrDate:~4,2%-100, day=1%CurrDate:~6,2%-100
rem compute several moduli needed for determining whether year is leap year
set /A yearMOD4=%CurrDate:~0,4% %% 4
set /A yearMOD100=%CurrDate:~0,4% %% 100, yearMOD400=%CurrDate:~0,4% %% 400
rem calculate %dayOfYear% as it were not a leap year
set /A dayOfYear=!accum[%month%]!+day
rem adapt %dayOfYear% only in case %month% is past February (29th)
if %month% gtr 2 (
rem check for leap year and adapt %dayOfYear% accordingly
if %yearMOD4% equ 0 set /A dayOfYear+=1
if %yearMOD400% neq 0 if %yearMOD100% equ 0 set /A dayOfYear-=1
)
rem compound statement to let %dayOfYear% survive SETLOCAL/ENDLOCAL block
endlocal & set dayOfYear=%dayOfYear%
rem return result
echo %dayOfYear%

Answer 3

This use the laps years in editable in loop | for /l %%L in (2020 4 2100) | < or more!
#echo off & setlocal enabledelayedexpansion && set "_cmd=Get Day^,Month^,Year^"
for /l %%L in (2020 4 2100)do set "_array_leap_year_=!_array_leap_year_!%%L,"
for /f "tokens=1-3delims= " %%a in ('wmic Path Win32_LocalTime !_cmd! ^| findstr /r "[0-9]"')do (
set "_yy=%%c" & set "_mm=0%%b" & set "_dd=0%%a" && set "_mm=!_mm:~-2!" & set "_dd=!_dd:~-2!" & set _date=!_yy!_!_mm!_!_dd!)
echo/!_array_leap_year_!|findstr /lic:"!_date:~0,4!," >nul&&(set "_leap_=29" & set "_year_=366")||(set "_leap_=28" & set "_year_=365")
set "_mm_dd_year_=01-31,02-!_leap_!,03-31,04-30,05-31,06-30,07-31,08-31,09-30,10-31,11-30,12-31" && set /a "_cnt=0" & set /a "_loop=!_mm! * 6"
(for /l %%d in (0 6 !_loop!)do set "_sum=!_mm_dd_year_:~%%d,5!" & if "9!_sum:~,2!" lss "9!_mm!" set /a "_day_year_+=!_sum:~-2!")
set /a "_day_year_+=!_dd!" && set /a "_remain=!_day_year_! - !_year_!" && echo/Today: !_date! ^| Day of Year: !_day_year_! ^| Days Remaining: !_remain:-=!
| Result | Today: 2019_04_21 | Day of Year: 111 | Days Remaining: 254
Conventional formatting:
#echo off & setlocal enabledelayedexpansion
set "_cmd=Get Day^,Month^,Year^"
for /l %%L in (2020 4 2100)do set "_array_leap_year_=!_array_leap_year_!%%L,"
for /f "tokens=1-3delims= " %%a in ('wmic Path Win32_LocalTime !_cmd! ^| findstr /r "[0-9]"')do (
set "_yy=%%c"
set "_mm=0%%b"
set "_dd=0%%a"
set "_mm=!_mm:~-2!"
set "_dd=!_dd:~-2!"
set _date=!_yy!_!_mm!_!_dd!
)
echo/!_array_leap_year_!|findstr /lic:"!_date:~0,4!," >nul && (
set "_leap_=29" & set "_year_=366" )||( set "_leap_=28" & set "_year_=365" )
set "_mm_dd_year_=01-31,02-!_leap_!,03-31,04-30,05-31,06-30,07-31,08-31,09-30,10-31,11-30,12-31"
set /a "_loop=!_mm! * 6"
for /l %%d in (0 6 !_loop!)do set "_sum=!_mm_dd_year_:~%%d,5!" && (
if "9!_sum:~,2!" lss "9!_mm!" set /a "_day_year_+=!_sum:~-2!" )
set /a "_day_year_+=!_dd!"
set /a "_remain=!_day_year_! - !_year_!"
echo/Today: !_date! ^| Day of Year: !_day_year_! ^| Days Remaining: !_remain:-=!