1 January

1 January was New Year's Day and the first day of the year on Earth.

Holidays and observances
As the first day of the year, 1 January was celebrated as New Year's Day. The year began with this day because, in 46 BC, Julius Caesar decided he'd start it on the shortest of all days — but when the priests complained, he made a compromise and used the first new moon after the shortest day of the year. This ended up being 1 January. (PROSE: The Doctor's Cross Word, Time Traveller's Diary)

Depending on the timestream, 1 January marked several New Year's Days in a row on the planet Apalapucia. (PROSE: Time Traveller's Diary)

Events
The very first New Year's celebrations took place in Mesopotamia, on land which would later become Iraq. The Thirteenth Doctor and her friends took part in the New Year's celebrations, which Graham O'Brien later expressed was his favourite of the twenty New Year's Eves they had visited in succession. (TV: Resolution)

In 1801, the Thirteenth Doctor and her companions discovered a dwarf planet with Giuseppe Piazzi. Yaz later recalled this as her favourite New Year's Eve. (TV: Resolution)

In 1888, Wovoka was cutting pine trees in the Nevada mountains when he fell into a crevice during a solar eclipse, and had a vision of a trailer for Michael Brookhaven's 1990 film The Coyote Road. This was a result of Faction Paradox's attempts to hijack the open door technology. (PROSE: The Book of the War)

In 1922, having waited around 28 years since he was displaced to 1894, the Ninth Doctor visited the nightclub in Birmingham where Rose Tyler would later be sent back herself. He returned to the club every evening this year to wait, until November when she did appear. (AUDIO: The Other Side)

In 1941, Professor Bernice Summerfield arrived on Guernsey in the English Channel. (AUDIO: Just War)

In 1966, the First Doctor's TARDIS departed Trafalgar Square, where it had arrived during the New Year's Eve celebrations. (TV: The Daleks' Master Plan)

Also in 1966, Jill and Bob Mason were married in Crook Marsham. Bob died of a brain aneurysm only four months later. (AUDIO: Nightshade)

In 1990, humanity subconsciously realised that there had been temporal discrepancies in the last two decades. Amara Essy, president of the United Nations Security Council, attended a secret briefing with Brigadiers Alistair Gordon Lethbridge-Stewart and Charles Crichton in Geneva to establish a dating protocol for the 1970s and 1980s. (PROSE: The Enfolded Time)

In 2000, the Eighth Doctor departed San Francisco, where he had landed two days earlier. He invited Grace Holloway to join him in the TARDIS, but she declined. The Doctor also did not accept Grace's invitation for him to come with her. However, they shared a goodbye kiss at the start of the new year. (TV: Doctor Who)

Also in 2000, Jack Harkness became the leader of Torchwood Three following the death of Alex Hopkins and the rest of the team, (TV: Fragments) the Fourth Doctor stopped the Voracians from utilising the Y2K bug from taking over the world in England (PROSE: Millennium Shock) while also, later in his timeline, visiting Paris with Romana II and confronting Taureau, (COMIC: The Forgotten) the Sixth Doctor and Melanie Bush saved the Earth from being taken over by Saraquazel and his servant, Ashley Chapel, (PROSE: Millennial Rites) and the Thirteenth Doctor and her friends watched the fireworks on the Sydney Harbour Bridge. (TV: Resolution)

In 2005, a dying Tenth Doctor finished the journey he deemed the "final reward" (TV: Death of the Doctor) when he visited Rose Tyler before she had met him. The Doctor commented that she was "gonna have a great year", then saw a vision of Ood Sigma and stumbled back to the TARDIS. He took flight into the Time Vortex and regenerated into the Eleventh Doctor. (TV: The End of Time)

In 2006, Mickey Smith gave up hope that Rose Tyler and the Doctor would ever return. (PROSE: Mickey's Blog)

In 2019, a Reconnaissance Dalek which had remained dormant since the 9th century was dug up by archaeologists Lin and Mitch. (TV: Resolution)

In 2022, the Thirteenth Doctor, Yaz, Dan, Sarah and Nick escaped a time loop from a squad of Dalek executioners. (TV: Eve of the Daleks)

In 2562, while aboard the Goodnight Dolly, Bernice Summerfield was named Master of Science and Archaeology for "shooting somebody". (PROSE: Genius Loci)

Behind the scenes
Resolution took place on the same day as its broadcast: 1 January 2019.