As the days grow shorter, artificial illumination has become a prominent feature of the winter landscape.
Diwali lights glow in many homes, Christmas displays await their formal switch-on in the town centre and shops are replenishing their stocks of Chanukah candles.
Market traders are also preparing to return to Broad Street in Oxford, while the distinctive smell of woodsmoke drifts through the surrounding area.
Expectations for the cold, dark festive period have been building since the autumn leaves began changing colour, prompting widespread feelings of nostalgia that can feel particularly intense.
Biological timekeeping may help explain some of that emotional response.
The human body normally follows a 24-hour circadian rhythm, although artificial light and excessive caffeine can interfere with it.
The experience of jet lag demonstrates just how closely the internal clock can regulate daily routines.
These biological mechanisms register more than the time of day; they can also detect the season.
Seasonal biological cycles, or circannual rhythms, occur in humans as well as animals.
Hibernating bears and swallows returning in spring offer familiar examples.
Changes in birth and death patterns across the year are among the documented forms of circannual rhythm.
Such patterns have become less pronounced as daily life has become increasingly detached from the natural indications of day length and temperature.
Nevertheless, recurring winter illness demonstrates that the body’s seasonal rhythms continue to operate.
The precise contribution these rhythms make to feelings of anticipation, joy or dread remains uncertain, although the effect resembles a documented psychological phenomenon called the anniversary effect.
The anniversary effect is most commonly associated with grief, but changes in the environment can also reactivate memories connected with a particular time of year.
It would nevertheless be premature to attribute the festive spirit entirely to environmental influences.
Smell may provide part of the explanation.
Olfactory memories can endure longer than memories formed through other senses, and autumn aromas can influence several aspects of wellbeing.
The relationship between scent, recollection and emotional health may account for the sense of wonder associated with the cooler months.
Seasonal traditions in different parts of the world frequently involve cinnamon, oranges, peppermint tea, dried fruit, biscuits and pine.
An aroma encountered at a particular time can prompt a strong emotional response or bring a childhood scene back into view.
The lingering scent of gunpowder during Guy Fawkes night or Chinese New Year celebrations can have the same effect.
The neurological basis for this response lies in the olfactory bulb, the region of the brain that processes smell.
It has direct physical links with the amygdala, which is involved in emotion, and the hippocampus, which is involved in memory.
Childhood memories are often especially easy to retrieve through scent.
Most scent-linked recollections are formed during the first decade of life, whereas visual and auditory memories tend to reach their peak during adolescence.
Certain aromas therefore appear to be closely associated with early childhood.
The arrival of winter can be both gloomy and magical.
Watching familiar films from the previous year or enjoying the aroma of pumpkin-spice lattes may consequently be understood as a response to biological mechanisms rather than simply a personal choice.