Convert Julian Day to Date in R (Example)

In this tutorial, I’ll show how to transform a Julian day to a calendar date object in the R programming language.

The post looks as follows:

So now the part you have been waiting for – the programming part:

Construction of Example Data

Initially, let’s create some example data in R:

my_julian <- 287                 # Create example Julian day
my_julian                        # Print example Julian day
# [1] 287

The previous output of the RStudio console shows the structure of our exemplifying data: It’s a simple integer value that corresponds to a Julian day.

Example: Convert Julian Day to Calendar Date Using as.Date() Function

The following R programming code illustrates how to get the calendar date that corresponds to a Julian day.

For this task, we can apply the as.Date function as shown below. Within the as.Date function, we have to specify the origin for our Julian day:

my_date <- as.Date(my_julian,    # Convert Julian day to date
                   origin = as.Date("2024-01-01"))
my_date                          # Print date
# [1] "2024-10-14"

The previous output shows the calendar date that corresponds to our Julian day, i.e. the 14th of October 2024.

Video, Further Resources & Summary

If you need further info on the R syntax of this tutorial, I recommend watching the following video which I have published on my YouTube channel. I explain the topics of this article in the video:

In addition, you might want to read the other tutorials which I have published on my website.

• Convert Date to Julian Day in R
• Convert Year, Month, Day, Hour, Minutes & Seconds to Date & Time
• Extract Day from Date in R
• Convert Date of Birth to Age
• Convert Date to Numeric Time Object in R
• Convert Date to Day of Week in R
• All R Programming Tutorials

In this post you have learned how to convert a Julian day to a calendar date in R programming. If you have further questions, don’t hesitate to let me know in the comments.