Temperatures are set to plummet to as low as -1°C to -3°C in the capital, with the outskirts of London experiencing temperatures as cold as -5°C.
That's colder than the snowy Reykjavík in Iceland, which has lows of 1°C forecast this week.
Met Office spokesman, Helen Roberts, told getwestlondon: "It's really from Wednesday onwards when we start to see a change in wind direction to an easterly, bringing cold air from the continent and that cold air looks like staying with us then for the rest of the week and into the weekend.
"So increasingly cold, widespread overnight frosts, risk of icy patches and then towards the last part of the week in particular, we start seeing a increasing chance of some showers pushing in which are likely to be wintry.
"I think there will be some snow showers, the air will be very cold by then.
"If you do get any snow showers, they are probably quite likely to settle on the ground.
"But the showers will be quite fleeting, so your not likely to get a big dump of snow."
During the first half of the week, the weather is expected to be quite damp and grey and it will feel quite chilly but no too cold, with highs on Tuesday, February 6 of 10°C.
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