Usage Note 38811: Julian Date - Business and ISO 8601 Usage
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Definitions of Julian dates
The term “Julian date” historically has been used by business users to denote the year and sequential day of the year.
For astronomers, “Julian date” is the number of days since noon GMT on Jan 1, 4713 BCE. This date was chosen because it is before recorded history.
Since 1988, ISO 8601 defines current Julian date usage as astronomers use it. This usage is becoming more common than the business use of Julian date – now called “Ordinal date”.
SAS functions, informats and formats
- DATEJUL Function
- JULDATE Function
- JULDATE7 Function
- JULIANw. Informat
- JULDAYw. Format
- JULIANw. Format
The items above all refer to what is now called “Ordinal date”. There are no current plans to change the names or functionality of these items.
SAS Date Values
A SAS date is a value that represents the number of days between January 1, 1960, and a specified date. SAS can perform calculations on dates ranging from A.D. 1582 to A.D. 19,900. Dates before January 1, 1960, are negative numbers; dates after are positive numbers.
- SAS date values account for all leap year days, including the leap year day in the year 2000.
- SAS date values can reliably tell you what day of the week a particular day fell on as far back as September 1752, the most recent time when the calendar was adjusted by dropping several days. SAS day-of-the-week and length-of-time calculations are accurate in the future to A.D. 19,900.
Conversion between SAS date values and Julian Date values
When the date falls in the range that can be represented as a valid SAS date, convert to Julian date by adding 2436934.5 to the SAS date value. The .5 compensates for the difference between the beginning of the day for a SAS date value (midnight) and beginning of a Julian Day (noon). If the date cannot be represented as a SAS date, you must derive your own formula.
Operating System and Release Information
| Product Family | Product | System | SAS Release | |
| Reported | Fixed* | |||
| SAS System | N/A | Macintosh | ||
| Macintosh on x64 | ||||
| Microsoft Windows 2000 Professional | ||||
| Microsoft® Windows® for 64-Bit Itanium-based Systems | ||||
| Microsoft Windows Server 2003 Datacenter 64-bit Edition | ||||
| Microsoft Windows Server 2003 Enterprise 64-bit Edition | ||||
| OpenVMS VAX | ||||
| z/OS | ||||
| Microsoft Windows XP 64-bit Edition | ||||
| Microsoft® Windows® for x64 | ||||
| OS/2 | ||||
| Microsoft Windows 95/98 | ||||
| Microsoft Windows 2000 Advanced Server | ||||
| Microsoft Windows 2000 Datacenter Server | ||||
| Microsoft Windows 2000 Server | ||||
| Microsoft Windows NT Workstation | ||||
| Microsoft Windows Server 2003 Datacenter Edition | ||||
| Microsoft Windows Server 2003 Enterprise Edition | ||||
| Microsoft Windows Server 2003 Standard Edition | ||||
| Microsoft Windows Server 2008 | ||||
| Microsoft Windows XP Professional | ||||
| Windows 7 Enterprise 32 bit | ||||
| Windows 7 Enterprise x64 | ||||
| Windows 7 Home Premium 32 bit | ||||
| Windows 7 Home Premium x64 | ||||
| Windows 7 Professional 32 bit | ||||
| Windows 7 Professional x64 | ||||
| Windows 7 Ultimate 32 bit | ||||
| Windows 7 Ultimate x64 | ||||
| Windows Millennium Edition (Me) | ||||
| Windows Vista | ||||
| 64-bit Enabled AIX | ||||
| 64-bit Enabled HP-UX | ||||
| 64-bit Enabled Solaris | ||||
| ABI+ for Intel Architecture | ||||
| AIX | ||||
| HP-UX | ||||
| HP-UX IPF | ||||
| IRIX | ||||
| Linux | ||||
| Linux for x64 | ||||
| Linux on Itanium | ||||
| OpenVMS Alpha | ||||
| OpenVMS on HP Integrity | ||||
| Solaris | ||||
| Solaris for x64 | ||||
| Tru64 UNIX | ||||
data _NULL_;
sas_date = '31jan2010'd; /* SAS Date input to formula */
julian_date = ceil(sum(sas_date,2436934.5));/* formula for Julian Day */
/* print results in SAS log */
put sas_date= date9. ' Ordinal date-formatted: '
sas_date julian7. ' ' julian_date= ;
run;
sas_date=31JAN2010 Ordinal date-formatted: 2010031 julian_date=2455228
| Type: | Usage Note |
| Priority: | |
| Topic: | SAS Reference ==> Functions ==> Date and Time ==> DATEJUL SAS Reference ==> Functions ==> Date and Time ==> JULDATE SAS Reference ==> Functions ==> Date and Time ==> JULDATE7 SAS Reference ==> Formats ==> Date and Time ==> JULDATE SAS Reference ==> Formats ==> Date and Time ==> JULIAN SAS Reference ==> Informats ==> Date and Time ==> JULIAN |
| Date Modified: | 2010-02-24 13:39:19 |
| Date Created: | 2010-02-19 16:22:56 |