And now, the health forecast for the coming week: a sudden drop in temperature will result in an increase in heart attacks by Thursday, but the weather generally is milder than this time last year so expect fewer flu and bronchitis patients.

It might be some years before the public gets quite such explicit guidance, but hospital managers with waiting list targets and GPs preparing their emergency cover are already benefiting from a new service from the Met office.

Trials in five areas - Plymouth, north Middlesex, Reading, Wolverhampton and Leeds - last winter, which cost £67,000, proved such a success that the Treasury has approved further funding to develop the scheme. The Royal Berkshire and Battle hospitals trust was able to organise an extra 100 non-urgent operations last December on the basis of the regular weather updates, 10% more than planned.

"Patients got their operations, the trust met its [waiting list] targets," said Heather Bunce, director of operations.

William Bird, a former GP who is the Met office's medical director, said the scheme could save the NHS millions. "There is evidence to link an increase in workload for a major health system like the NHS, due to respiratory infections and trauma, with the weather."