While temperatures drop, homes across the UK, we are gradually firing up the central heating.
Each autumn - or earlier, if summer is particularly disappointing - there's an argument that sunders households up and down the country.
Can we turn on the radiators yet? Or should we save cash by keeping the heating switched off for as long as possible?
For many people - especially those on low incomes - it's an acute financial conundrum. Energy bills have risen by 28% over the past three years, according to regulator Ofgem, putting pressure on family budgets.
But what often exacerbates these domestic rows is that, for a variety of reasons, some people are simply better at tolerating drops in temperature than others.
Factors such as age, physiology, gender, geography and even hair colour will affect how much each individual feels the cold, say experts.
For some people, however, turning on the heating is a symbolic ritual marking the changing of the seasons - and despite an unusually warm British summer coming to an abrupt halt, many are stubbornly determined to delay it as long as possible.
'Man up, put a sweater on'
There is a significant gender divide when it comes to feeling the cold, according to Mike Tipton, professor of physiology at the University of Portsmouth,
In low temperatures, he says, the body reacts by diverting blood to the vital organs, and makes the extremities - the head, hands and feet - feel chillier. Oestrogen makes the vessels that shut down blood flow to the skin more sensitive.
As a result, he says, "it tends to be females that complain of cold hands and feet". While a woman's core body temperature may be the same as a man's, her skin is likely to feel cooler.
But there are other physical factors that make a difference, too.
People who are physically fit have better circulation, which makes them feel warmer, says Tipton.
Conversely, he says, excess fat insulates the deep body temperature of overweight individuals. Fatter people also tend to have lower skin temperatures, meaning they are used to the cold.
A 2005 study by researchers at Louisville University in Kentucky suggested that people with ginger hair may be more sensitive to the cold than brunettes - somewhat confounding the stereotype of the redhead as a hardy Celt.
People really underestimate how much of a difference a well-insulated house can make.
The UK's ageing housing stock means this is a common problem. Anti-fuel poverty campaigners and environmentalists alike have called for action, but a wide-ranging solution has proved elusive.
In June it was reported that only four people had signed up to the Green Deal, a flagship government policy launched six months earlier to help householders make energy efficiency improvements.
For many, however, delaying putting on the heating is a matter of financial necessity as energy costs soar.
A ComRes survey for BBC Radio 5 live earlier this month found 25% of people had put up with an "unacceptably cold" house during the past year to keep their bills down.
Some 63% of the 1,035 adults interviewed said they had reduced their energy use due to rising costs.
But it isn't just because of poverty or desperation that some people prefer to shiver rather than turn on their radiators. There's a certain type of person who takes pride in keeping the boiler out of action for as long as possible.
If you know you can afford to put the heating on, it becomes this fun game, But if you're poor, living in an unheated house is just miserable.
Whatever people's reasons for tolerating what others would regard as freezing conditions, another autumn of conflict about what is a comfortable temperature is as inevitable as the changing of the seasons.
from the BBC