Winter

Winter was a season on Earth, notable for usually being cold. It followed autumn and was followed by spring then summer. (TV: The Mutants)

According to the Twelfth Doctor, Frozen was a movie which featured an eternal winter. (TV: Empress of Mars)

History
Before meeting the First Doctor, the Tribe of Gum lost their last firemaker. They were unable to cook their food and were freezing during the winter because of this. (TV: An Unearthly Child)

River Song was taken by the Doctor for her birthday to the last Winter Frost fair on the River Thames in 1814. Stevie Wonder unknowingly performed before being taken back to his original time. (TV: A Good Man Goes to War)

Walter Simeon and the Snowmen, accomplices of the Great Intelligence, anticipated the last winter of humankind in 1892. However, they were thwarted by the Eleventh Doctor. (TV: The Snowmen)

On the Western Front of the First World War, the winter of 1916 was particularly harsh. (PROSE: Doctor Who and the War Games)

During World War II, Nazi Germany temporarily shelved plans to invade the United Kingdom as the winter of 1940 set it. The following year, winter in Russia brought the German forces to a halt after they invaded the Soviet Union in 1941. The Red Army used the opportunity to counterattack, driving the Germans back from Moscow. (PROSE: Just War) Winter arrived again in late 1942 after the Germans began their attack on Stalingrad. Many Russian civilians froze to death. (PROSE: The Beast of Stalingrad)

The severity of the winter at the beginning of 1963 was caused by the Cold. It stretched on into March and early April with unnatural snow storms before the First Doctor decided to intervene and sent the Cold to Pluto. (PROSE: Time and Relative)

Winter on other planets
One umnamed planet colonised by human s experienced winter lasting 500 year s. The only settlement on the planet was named the city of Winter in reference to this. The Dalek s took advantage of the winter in order to maintain control of the planet, providing the colonists with artifical sunlight to help with harvest s in order to appear benevolent. (AUDIO: The Dalek Occupation of Winter)

Vostok III was known for its cold winters. (AUDIO: The Haunting of Malkin Place)

Information from invalid sources
Actor Paul McGann once commented on the odd nature of filming a scene set in Winter in July. (NOTVALID: Father Time: "Set Visit")