The warmest New Year's Day on record will be followed by ice and snow across parts of the country this week, the UK Health Security Agency (UKHSA) has warned.
The Met Office said that the North East of England, North West of England and Yorkshire and Humber regions will be particularly susceptible to cold weather from midnight on Tuesday 4 January until midday on Thursday 6 January.
It means hundreds more households could be due a Cold Weather Payment on their energy bills.
Cold Weather Payments can help struggling households pay their bills during periods of especially bad weather.
It's run by the Department for Work & Pensions (DWP) and applies every winter.
Sub-zero temperatures mean many households could be eligible for a £25 energy discount
The scheme kicks in on November 1 and ends on March 31 – it applies when temperatures fall to zero degrees or less for seven or more consecutive days.
Agostinho Sousa, a consultant in Public Health Medicine at UKHSA, said: "Cold weather can have a serious impact on health, particularly for older people and those with heart and lung problems, as it increases the risks of heart attacks, strokes and chest infections.
The first Cold Weather Payments of the year were triggered in December
"It’s important to check on those who are more vulnerable to cold weather, including older neighbours or relatives – especially those living alone or those who have serious illness.
"Remind them to heat their home to at least 18 Celsius, 64.4 Fahrenheit and to keep up to date with the forecast."
Met Office chief meteorologist Neil Armstrong said: Following an exceptionally mild spell, temperatures are set to drop for many in the north of England from late on Monday and into Tuesday. This drop in temperatures will spread further south later on Tuesday.
"This change is being brought on by a cold northerly flow, which brings with it the risk of some wintry showers in places in northern England, especially over high ground. Minimum temperatures over the next few days are expected to drop below freezing, heightening the risk of some ice formation."
The qualifying postcodes so far this winter are listed below – if you're eligible, the money will be paid into the account registered with your state benefit.
For more weather alerts, see our updates here.
What is a Cold Weather Payment?
Cold Weather discounts are paid out by the Government during times of freezing weather – they equate to £25 per week.
The money goes to people on low incomes who receive a qualifying benefit, such as pension credit or certain employment benefits, when temperatures sink to below 0°C in the area they live in.
Payments are triggered by data collected by the Met Office from 94 weather stations around Britain.
The scheme runs each year from November 1 to March 31 every year.
If you do qualify, you'll get a £25 a week payment for every seven-day spell of cold weather you experience.
Cold Weather Payments checker – find out if you qualify
If you're experiencing freezing weather in your area, you can find out if you're owed money by entering your postcode in to the DWP's online finder.
Energy Saving Discounts
Cold Weather Payments
£140 Warm Home Discount
When to turn your heating on for winter
Winter Fuel Allowance
How to claim a £25 Cold Weather Payment
If you qualify for a Cold Weather Payment, you’ll be paid automatically after each seven-day period of freezing weather. This money should arrive in the bank account you already have registered with the DWP – and payments should be made within a fortnight.
Contact the pension centre or your local Jobcentre Plus office if you think you should have received a Cold Weather Payment but didn't.
The Universal Credit helpline on 0800 328 9344 can also be used.
Meanwhile, if you've had a power cut due to bad weather this winter, here's how to get an energy refund.
Who qualifies for a Cold Weather Payment?
Cold Weather subsidies are paid to people on low incomes who receive a qualifying benefit, such as Universal Credit or certain employment benefits.
Millions people aged 65 and over also meet the criteria for winter fuel payments every year because they're older and vulnerable. This is usually linked to Pension Credits.
Below is a list of the benefits you'll need to be in receipt of (read more on whether you qualify for benefits, here) :
Income-based Jobseeker's Allowance
Income-based Employment and Support Allowance
You can keep up to date on the weather on the Met Office's twitter page.
How cold does it have to be?
The average temperature in your area needs to have been 0˚C or less for a week or more. This must be based on Met Office readings.
Where Cold Weather Payments been triggered so far this winter
See all the qualifying postcodes so far this winter below
If you've experienced freezing temperatures in the past two months, check your postcode to see if your area qualifies for a £25 payment.