Storm Hannah is set to batter parts of Britain this weekend, with gusts of up to 75mph.
After a baking hot Easter weekend, heavy rain and strong winds throughout Saturday are likely to make conditions feel colder, the Met Office said.
Temperatures are forecast to drop into the low teens, slightly below the average for the time of year.
Ireland is set to bear the brunt of the storm, with the country's weather service issuing an orange status advisory for large parts.
Storm Hannah was named by Irish forecaster Met Eireann.
While the strength of the storm will tail off as it moves across Britain, some parts will see increasingly unsettled weather.
The south west of the UK is expected to see the worst of Storm Hannah, with the Met Office issuing a yellow weather warning from Friday night until Saturday afternoon.
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South Wales is also expected to be hit by Storm Hannah and has been placed under a yellow weather warning.
The yellow wind alert for the southwest of England and south Wales will come into force at 9pm.
The revised forecast has the worst of the storm hitting the south and middle of the country, with the yellow warning stopping north of Manchester.
Storm Hannah is expected to clear the UK by Sunday, meaning decent weather for those taking part in the London Marathon, and more settled conditions are expected to return next week.
Met Office chief forecaster Frank Saunders said: "We're going to see an unsettled period over the next few days, but the forecast for later next week indicates the return of high pressure, bringing more settled conditions.
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"Storm Hannah will move away from the UK during Saturday followed by a transient ridge of high pressure bringing more settled weather to the UK for Sunday, good news for London Marathon runners."
Alex Deakin, a Met Office meteorologist, said: "It will be such a shock when you compare it to last Saturday. Some places could be 15C lower than last Saturday. It's incredible, really.
"Some places through Saturday may be struggling in the single figures, while last Saturday we were in the mid 20s."
Less than a week ago temperatures hit 25.5C on Easter Saturday, leading to the hottest ever Easter Monday.
Fortunately for London Marathon runners and supporters clear skies are forecast over the capital on Sunday.
