Winter Solstice on December 21st. This is officially the longest night of 2017, (even though the year's earliest sunset for the UK occurs two weeks earlier). The Geminid meteors on the night of the 13th-14th. Watch out for this reliable shower.
Capricornus, the Sea Goat: Sign of the Zodiac for birth dates between 22 December and 19 January; it is the leading constellation of the "wet" or "water" constellations. Capricornus has a symmetrical shape resembling a bikini bottom, but the stars of Capricornus are very faint with no star brighter than the third magnitude. Capricornus appears low in the southern sky (never at higher altitudes). The Tropic of Capricorn (23.5 degrees South latitude) is named after Capricornus; on 22 December (on average), the Sun is directly overhead (at the zenith) at Noon along the Tropic of Capricorn. In Mythology, the Greeks identified Capricornus with Pan, the god of nature, who was pictured as half-man, half-goat. In fear, Pan escaped the giant Typhon by leaping into the Nile River and changing his tail to that of a fish. This is the origin of the word, "panic."
There are many meteor showers this month... The Geminid Meteors Shower Peaks on the night of the 13th-14th. The Coma Berenicids are a poorly-known minor shower, and badly need more observing. Very swift meteors, (65km/sec). Their Radiant is at RA 11h40m Dec +25°. Ursids Meteor Shower Peaks on the 22nd. A minor shower. The radiant (RA 14h28m Dec +76°) is circumpolar (It never sets in northern locations). The meteors are generally slow (33km/sec) and rates are lower than the Geminids, but certainly above the background sporadic count. The Ursids are linked with Comet 8P/Tuttle (period around 13.5 years; last at perihelion in 1994). Their peak rates can be quite variable. Also, watch out for sporadic meteors. Their rates for the Northern Hemisphere are now reaching a plateau. Expect around 12 random meteors per hour during the morning hours