Converting fractional doy (eg. 208.572917) to a date with mm/dd/yyyy HH:MM

I have a set of data that includes doy for the year, 2013, but the doy are fractions such that July 27th at 13:45 would be represented as 208.5729167. I would like to convert this to a visual that is easier to interpret such as mm/dd/yyyy HH:MM. I've searched around and the closest function I've found converts a date to doy.

Thanks in advance

Answer 1

[Walter Roberson]

datestr(208.5729167 + datenum('2013/01/01'),'mm/dd/yyyy HH:MM')

[mbhd]

Works great, thank you! Only correction I have is that instead of 2013/01/01, 2012/12/31 should be used because this gives the accurate date since doy 208 already accounts for the 1st of the year.

Answer 2

[Peter Perkins]

In R2014b or later, you can use datetime and duration:

>> d = datetime(2013,1,1) + days(208.5729167)
d = 
   28-Jul-2013 13:45:00

But bear in mind that in double precision, hours, minutes, and seconds are not exactly representable as fractions of days. Hope this helps.