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December 31

Day 366 of 366 · ISO week 1 · Capricorn · Winter (Northern Hemisphere)

December 31 is the 366th day of the year in the Gregorian calendar; 0 days remain until the year's end. It falls in winter (northern hemisphere) and under the astrological sign of Capricorn.

Day of year
366
Days remaining
0
ISO week
1
Zodiac
Capricorn
Season
Winter
Sun declination
-23.0°

External references

Curated jump-off points to the major almanacs, encyclopaedias and primary sources for this date.

Wikipedia: this day →Britannica: this day →LoC: Today in History →History.com: this day →On-This-Day.com →BBC: On This Day →NYT: this day →Time and Date →NASA APOD archive →U.S. Naval Observatory →Wolfram|Alpha →Wikidata →Google Books →JSTOR →Internet Archive →
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Astronomy

Solar declination through the year — the Sun's apparent latitude on Earth. December 31 ≈ -23.0°
+23° −23° -23.0°
Computed via Cooper's formula. Positive declination = Sun north of the celestial equator (Northern Hemisphere summer).

On December 31 the Sun's declination is approximately -23.0°. At this latitude the Sun is south of the celestial equator, giving the Northern Hemisphere shorter days than nights.

For specific rise/set times at your location, see the U.S. Naval Observatory, or the NASA APOD archive for any imagery published on a December 31.

Position in the year

Position in the calendar year — day 366 of 366 (with 0 remaining)
JanFebMarAprMayJunJulAugSepOctNovDec Dec 31

Holidays & observances

No widely-observed holidays catalogued for this day in our base set. See the external almanacs above for region-specific observances.

Events

A selection of widely-documented historical events that took place on this date. Years marked BCE follow standard astronomical convention.

No events currently catalogued for this day. External references may have more.

Notable births

No births currently catalogued for this day. External references may have more.

Notable deaths

No deaths currently catalogued for this day. External references may have more.

Numerical & calendrical curiosities

Day-of-year (366)2 × 3 × 61 · composite (no)
Days remaining (0)0
Date code DDMMYYYY31122026 · next palindrome year: 2113
Sun declination-23.00° (Cooper approximation)
Distance from solstice11 days

Cross-references

The 31st of every other month

Adjacent days

Days nearby

All days