Household gas bills for December will be the highest to date after the Met Office confirmed the UK had suffered the coldest December since 1890.
Gas bills will average £227, which is £44 more than they would have been if temperatures for December had been at normal levels.
Gas charges were actually higher in late 2008 when oil prices reached $147 (£94) a barrel but temperatures were lower at the time so bills averaged just above £200.
The Met Office said its provisional data for 1-30 December put the average temperature in the UK at -0.4C (32F), more than 5C lower than normal. The charity National Energy Action (NEA) estimates that for every degree below the seasonal norm, households spend an extra 29p per day to heat their homes.
From Tuesday, six million npower customers will have to pay 5.1% more for their electricity and gas, an average of £54 extra per year.
Before Christmas, British Gas, Scottish Power and Scottish and Southern Energy introduced similar rises. Average annual electricity and gas bills will be £1,239 from 4 January.
The rises, together with the freezing weather, will greatly increase the number of people in fuel poverty – defined as households spending more than a 10th of disposable income on utility bills. NEA estimates that 5.1m households – more than one in five – were in fuel poverty before the latest price rises kicked in.
Energy suppliers blame the recent tariff hikes on the rising cost of buying gas on the wholesale market, even though prices are falling globally as a result of a glut in supplies.
In November, the regulator Ofgem announced it was reviewing whether the profits made by the industry were too high. Energy experts pointed out there have been 18 such reviews since 2001 conducted by Ofgem, MPs, the European commission, the Competition Commission and the government, but they have resulted in little action.
The Met Office said December was the third driest, and sunniest, since 1910. Despite the nation freezing, there were 53 hours of sunshine and 45.1 millimetres of rain and snow, compared with 32.4 millimetres in 1933, the driest on record.
Records for national average temperatures only began in 1910. Before then, figures were only kept for central England, chosen because it usually experiences average temperatures. Last month's provisional average of -0.4C was the coldest since December 1890, when central England experienced an average of -0.8 C.
The average national December temperature of 4.7C is from records taken between 1961 and 1990. Experts say this is most accurate as it predates the most dramatic effects of global warming when winters have generally become cooler.
