Hi Joe, Ferret does not currently use the alternative name "365_day" for noleap, though that was an oversight and we'll add that name as an equivalent to "noleap". In addition, note that in the Ferret documentation says, "... the use of calendars beyond the defined Gregorian, Julian, noleap, and 360 day calendar are not implemented at this time.) " so the all_leap or 366_day calendar listed in the CF document is not allowed. Ferret implements the proleptic_gregorian calendar for standard or Gregorian calendars if their time span extendeds to dates before 1582-10-15 (rather than the historic calendar that was in place before 1582). Joe McLean wrote: Hi All, |