Recognised as Date
31 December 1378
- Thursday
- Q4
- Common year
- Week 53
- Capricorn
31 December 1378 falls on a Thursday in the proleptic Gregorian calendar, which did not yet exist at the time. It is day 365 of 365 in 1378, falling in week 53 and quarter 4. Its Unix timestamp is -18,650,217,600.
Calendar position
Day of the weekThursdayproleptic Gregorian; contemporaries used the Julian calendar and would have named a different day
Day of the month31st
Day of the year365 of 365
Days remaining in the year0
Days elapsed in the year364
ISO week numberWeek 53ISO 8601, weeks start on Monday
Week of the month5th
Occurrence in the month5th Thursday, and the last of the month
QuarterQ4 1378
Year1378
Days in the month31
Leap yearNo, 365 days
This date in other formats
ISO 86011378-12-31
British (D/M/Y)31/12/1378
American (M/D/Y)12/31/1378
Long formThursday 31st December 1378
RFC 2822Thu, 31 Dec 1378 00:00:00 GMT
Compact13781231
In wordsthe 31st of December, one thousand, three hundred and seventy-eight
Julian calendar equivalent23 December 1378the date contemporaries would have written, before the Gregorian calendar existed
This date in other calendars
Hebrew3 Tevet 5139the Hebrew calendar has been fully algorithmic since the ninth century, so this is exact
Islamic (tabular)2 Ramadan 780 AHthe tabular reckoning; the calendar in religious use begins each month on an actual crescent sighting, so expect a day either way
Persian (arithmetic)10 Dey 757the arithmetic (Birashk) calendar; the official Solar Hijri calendar takes its new year from the astronomical equinox at Tehran
Rata Die503,304days since 1 January 1 CE in the proleptic Gregorian calendar, the pivot every conversion here runs through
Unix time & day counts
Unix timestamp-18,650,217,600seconds since 1 January 1970, midnight UTC
Unix timestamp (ms)-18,650,217,600,000
Relationship to the epoch215,859 days before the Unix epoch
Julian Day Number2,224,729midnight UTC
Days since 1 January 1900-190,292
Days since 1 January 2000-226,816
Moon phase
PhaseWaxing crescentthe same phase everywhere on Earth at the same instant
Illuminated at 12:00 UTC10%≈to about 1%, by Meeus
Waxing or waningWaxing
Moon age at 12:00 UTC2.9 dayssince the previous new moon
Previous new moon28 December 1378
Next new moon27 January 1379
Previous full moon12 December 1378
Next full moon11 January 1379
Lit side, Northern HemisphereRight
Lit side, Southern HemisphereLeftthe same Moon seen from the other side of the equator; near the equator the lit side points up or down rather than to one side
PrecisionDates onlybefore 1700 or after 2150 the Earth's rotation is not known well enough to give a time, and a phase near midnight can land a day either side
Relative to today
These values depend on today’s date and change daily.
Today19 September 2026
Days ago236,574 days
In other terms647 years, 257 days and 6 hours
Weeks33796.3 weeks ago
Anniversary this yearin 103 days
Years elapsed647 complete years
Seasons & signs
Zodiac signCapricornEarth sign
Chinese zodiac yearHorsethe animal changes at Chinese New Year, not 1 January
Season (Northern Hemisphere)Wintermeteorological seasons, by whole months
Season (Southern Hemisphere)Summer
Easter Sunday that year29 March 1378
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