Weather: Why our winters are unavoidably delayed

The days have been getting longer, and the sun higher in the sky, since 23 December. So why does our weather grow colder throughout January and February? The answer lies in the efficiency of the oceans as storage heaters.

We all know that it's cold in winter because the tilt in the earth's axis of rotation points us away from the sun at this time of year. We can see the sun lower in the sky, and the dark mornings and early sunsets confirm that we are receiving less solar warmth. So far, so good; but if the shortest day of the year - which must be when we receive the least solar energy - falls a few days before Christmas, why does the weather continue to get colder for the next couple of months?

The way the sun provides warmth is not as simple as it seems. Since the air is a poor conductor of heat, most of the warmth we feel round us is radiation from the Earth itself. The sun heats up the Earth, which then warms up the air by radiation. This explains why the higher you go, the colder it gets. The top of a mountain may be nearer to the sun, but that counts for nothing compared with the fact that it is farther away from the nice warm ground.

What makes the real difference, however, is the difference between the land and the sea. Water is far more efficient than land at storing heat. Indeed, it may be said that the oceans are a reservoir not only of water, but also of the world's heat. Not only are the waters more efficient at storing heat, but it takes more heat energy to warm them up in the first place. This results in the oceans providing a sort of temporal thermal lagging around the continents. Water temperatures will rise and fall more slowly than those of nearby land.

Both the land and the sea warm up during the periods of maximum sunshine, then gradually cool down, radiating their warmth into the air. When the sun is less generous with its energy, the world cools down, and needs some time to warm up again before we begin to feel the benefit. We are living on a massive storage heater, simultaneously operating on two different tariffs: the quick-release land storage and the slow-release ocean storage.

Over land that is far from the sea, there is about a one-month time-lag between the shortest day and the coldest day (or the longest day and the hottest day). Over the oceans it is about two months. In Britain, where our weather is dominated by the seas around us, the hottest day of the year generally falls in the middle of August (it was 10 August last year) - two months after the summer solstice.

One aspect of all this, however, remains perplexing: if there is such a time-lag between our receiving solar energy and experiencing its effects, why is long-range weather-forecasting still such an inaccurate science? One might naively think that with all the solar energy stored up a month or two in advance, we ought to be able to predict what will happen when it is released. Yet it does not seem to work like that. The diffusion of heat between various sea depths, and the vagaries of heat transfer by ocean currents, seem to make predictions impossibly difficult.

As with so many aspects of the weather, the key to successful long-term forecasting is a better understanding of the oceans.

Barn owls are among species that could be affected
charity appeal
Sarah Silverman (middle) with sister Reform Rabbi Susan Silverman (right) and sister actress Laura Silverman (left) at Jerusalem's Western Wall for feminist Hanuka candle-lighting ceremony
peopleControversial comedian stages pro-equality Hanukkah lighting during a protest at Jerusalem's Wailing Wall
Arts and Entertainment
The Bach Choir has been crowned the inaugural winner of Sky Arts’ show The Great Culture Quiz
arts + ents140-year-old choir declared winner of Sky Arts' 'The Great Culture Quiz'
After another poor series in Sri Lanka, Alastair Cook claimed all players go through a lean period
cricketEoin Morgan reportedly to take over ODI captaincy
Have you tried new the Independent Digital Edition apps?
Life and Style
ebookNow available in paperback
Life and Style
ebooksA superb mix of recipes serving up the freshest of local produce in a delicious range of styles
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating

By clicking 'Search' you
are agreeing to our
Terms of Use.

ES Rentals

    iJobs Job Widget
    iJobs General

    Recruitment Genius: Finance Director

    £65000 - £80000 per annum: Recruitment Genius: Finance Director required to jo...

    Recruitment Genius: Medico-Legal Assistant

    £15000 - £25000 per annum: Recruitment Genius: This is a unique opportunity fo...

    Ashdown Group: (PHP / Python) - Global Media firm

    £50000 per annum + 26 days holiday,pension: Ashdown Group: A highly successful...

    The Jenrick Group: Quality Inspector

    £27000 per annum + pension + holidays: The Jenrick Group: A Quality Technician...

    Day In a Page

    Homeless Veterans appeal: 'You look for someone who's an inspiration and try to be like them'

    Homeless Veterans appeal

    In 2010, Sgt Gary Jamieson stepped on an IED in Afghanistan and lost his legs and an arm. He reveals what, and who, helped him to make a remarkable recovery
    Could cannabis oil reverse the effects of cancer?

    Could cannabis oil reverse effects of cancer?

    As a film following six patients receiving the controversial treatment is released, Kate Hilpern uncovers a very slippery issue
    The Interview movie review: You can't see Seth Rogen and James Franco's Kim Jong Un assassination film, but you can read about it here

    The Interview movie review

    You can't see Seth Rogen and James Franco's Kim Jong Un assassination film, but you can read about it here
    Serial mania has propelled podcasts into the cultural mainstream

    How podcasts became mainstream

    People have consumed gripping armchair investigation Serial with a relish typically reserved for box-set binges
    Jesus Christ has become an unlikely pin-up for hipster marketing companies

    Jesus Christ has become an unlikely pin-up

    Kevin Lee Light, aka "Jesus", is the newest client of creative agency Mother while rival agency Anomaly has launched Sexy Jesus, depicting the Messiah in a series of Athena-style poses
    Rosetta space mission voted most important scientific breakthrough of 2014

    A memorable year for science – if not for mice

    The most important scientific breakthroughs of 2014
    Christmas cocktails to make you merry: From eggnog to Brown Betty and Rum Bumpo

    Christmas cocktails to make you merry

    Mulled wine is an essential seasonal treat. But now drinkers are rediscovering other traditional festive tipples. Angela Clutton raises a glass to Christmas cocktails
    5 best activity trackers

    Fitness technology: 5 best activity trackers

    Up the ante in your regimen and change the habits of a lifetime with this wearable tech
    Paul Scholes column: It's a little-known fact, but I have played one of the seven dwarves

    Paul Scholes column

    It's a little-known fact, but I have played one of the seven dwarves
    Fifa's travelling circus once again steals limelight from real stars

    Fifa's travelling circus once again steals limelight from real stars

    Club World Cup kicked into the long grass by the continued farce surrounding Blatter, Garcia, Russia and Qatar
    Frank Warren column: 2014 – boxing is back and winning new fans

    Frank Warren: Boxing is back and winning new fans

    2014 proves it's now one of sport's biggest hitters again
    Jeb Bush vs Hillary Clinton: The power dynamics of the two first families

    Jeb Bush vs Hillary Clinton

    Karen Tumulty explores the power dynamics of the two first families
    Stockholm is rivalling Silicon Valley with a hotbed of technology start-ups

    Stockholm is rivalling Silicon Valley

    The Swedish capital is home to two of the most popular video games in the world, as well as thousands of technology start-ups worth hundreds of millions of pounds – and it's all happened since 2009
    Did Japanese workers really get their symbols mixed up and display Santa on a crucifix?

    Crucified Santa: Urban myth refuses to die

    The story goes that Japanese store workers created a life-size effigy of a smiling "Father Kurisumasu" attached to a facsimile of Our Lord's final instrument of torture
    Jennifer Saunders and Kate Moss join David Walliams on set for TV adaptation of The Boy in the Dress

    The Boy in the Dress: On set with the stars

    Walliams' story about a boy who goes to school in a dress will be shown this Christmas