Bad weather, debt, seasonal blues and failed resolutions mean today is miserable Monday, says one scientist.
Cardiff University tutor Cliff Arnalls says his formula proves 24 January is the grimmest day of the year. And many of your emails agreed.
But, readers told the Magazine, there are reasons to beat back the winter blues and be cheerful in January.
Here are ten of the best:
1. Happy Birthday. "I was born on this day and I light up everyone's life," said Loz, from Eastbourne, one of an estimated 163,049 Britons celebrating their birthday on Monday.
Others were less enthusiastic. David Petitti from Chicago wrote: "My father's birthday is this day. Darkness rules the earth, the biting cold saps energy and spirit. Dad's birthday truly does stink."
JANUARY BLUES DAY FORMULA
1/8W+(D-d) 3/8xTQ MxNA. Where:
d: Money due in January pay
T: Time since Christmas
Q: Time since failed quit attempt
M: General motivational levels
NA: The need to take action
2. The money. Dread it? "No, I can't wait for it. It's pay day!" said Cameron Costigan, from London. Monday's first pay cheque of 2005 comes at the height of the bonus-payment season for city workers.
"Bonuses are definitely better than last year," says Philip Marks, of recruitment firm Jonathan Wren. They could be a 10-20% salary bonus for middle office staff and 40-100% for top traders.
3. Burns Night. "We're lucky in Scotland to have Burns' Night on 25 January - a great excuse to get together with friends, eat far too much and have a few drinks," said Bruce Freshwater, from Edinburgh.
Other winter festivities are long gone, but the Scots will spend Monday preparing to honour balladeer and people's champion Robert Burns, with supper, pipes and poetry.
They are not alone - one supermarket predicts more of its 200,000 haggis will be sold south of the border - with curry or hot and spicy varieties popular.
4. Up sticks. "Move to Spain. Winter is but a distant memory," wrote Eugene Martin, from Madrid, Spain. "You yellow-toothed limeys really know how to whinge. Come on over to Florida - January is great," said Richard Busch in Pensacola.
Relocation is "the new Porsche" of status symbols, according to Peter Robinson of Homes Overseas magazine. And January is the month people look to do it.
Canadians do cold properly
In 2004, 200,000 Britons were considering buying an overseas property, he says. Of those, 30% were expected to do it within a year.
5. Canada's worse. Carla, in Ottawa told us: "Here, we are expecting a heatwave on Monday: it's predicted to rise to -9 C. Folks will be out in shorts, dancing in the streets."
"You know its cold, when you go into a fridge to warm up," said Tony from Toronto.
"The worst part is that the snow doesn't go away here until May," said James in Winnipeg, Canada.
Jeff Connolly in London, Ontario summed it up: "I am from Canada, and you don't need a Monday to feel crummy. Up here, all you need is winter."
6. Solstice solace. "It's getting lighter; I have snowdrops and crocus in flower: what's to be depressed about?" asked Shirley, in Leeds.
There is hope: Monday is more than a month after the winter solstice, December 21, and less than two months before the first day of Spring - for astronomers, the vernal equinox on 20 March.
On Met Office UK averages, January has less rain (51.9mm compared to 54mm) and more sunshine (45.9hrs, 37.8hrs) than December.
7. Get out there. "Exercise and kisses really are a great boost!" said Sonny Dumas, from Amsterdam.
Exercise lifts the mood
"Put on a pair of running shoes and do a run around the block - makes you feel so much better, physically and mentally," said Richard Eames, from New York. Beulah in Shropshire said: "I put on my wellies on and spend a day outdoors."
The health and mood benefits of exercise are well-documented.
8. You do the maths. Monday might be fine after all - the worst day formula is "rubbish" said some correspondents.
"How do you put a numerical value on weather, motivation, and initiative?" asked Keith in Canmore, Canada.
"Pseudo-scientific babble with no basis in serious science," said Alan in Dublin.
"I could keep ranting, but I have proper research to do!" concluded Rowan Temple, in Birmingham.
9. Count your blessings. Recognise how lucky you are was the serious note from many.
"At least we are alive to see another day and sort things out," said Anne Gardiner, in Cranfield, Bedfordshire.
10. The hills are alive. "The best way to beat the blues is to watch the film The Sound of Music. The heady mixture of drama, action, romance and music lifts the spirits no end," admitted Ketan B Shah, from Harrow.
Robert Mitchell, of trade paper Screen International, would not be drawn on the benefits of watching the 1965 curtain-clad Julie Andrews war classic ("Musicals aren't my bag").
But he said January sees plenty of quality cinema releases alongside blockbusters for the Hollywood award season.