The coldest Lunar New Year holiday in the past 16 years kept Hongkongers from visiting the doctor.
The number of emergency cases at public hospitals this new year fell by more than 1,000 cases a day on average, compared with last year.
From January 23 to January 25 - the first three days of the Lunar New Year - the city's public hospitals received an average of 5,557 emergency cases each day.
That was 1,211 cases fewer than the last Lunar New Year, which saw 6,768 cases a day.
The daily average over the three public holidays was also 5.3 per cent lower than the daily average for the whole of this month to date.
There were 29 hypothermia cases recorded at public hospitals from January 23 to January 25, with patients aged from 38 to 98.
A further 10 people were admitted to hospital for hypothermia yesterday, bringing the total to 39 since the Lunar New Year.
Dr Lee Ka-hing, of Union Hospital's department of emergency medicine, said the figures for private hospitals mirrored those at their public counterparts.
He said the number of patients at his hospital's emergency ward dropped by one-fifth during the three public holidays this year, compared with last year.
Lee said the cold weather was one of the reasons patients did not leave home to visit the hospital for a minor illness. 'But the patients that we see [at the hospital] would be more serious cases,' Lee said.
Patients - especially children - frequently visit the emergency ward for fevers and stomach viruses, Lee said. This year's flu season was also slightly less serious compared with the same period last year, he said.
'We've seen a lot of gastroenteritis cases, maybe because people have eaten a lot and may not have paid attention to whether their food was clean during the holidays,' said Lee.
The stomach virus, or stomach flu, is not related to influenza, but is caused by consuming ill-prepared food and drink, or food infected with bacteria.
Symptoms include vomiting, diarrhoea and abdominal pain.
The Observatory recorded a record low of 7.4 degrees Celsius at its Tsim Sha Tsui headquarters on January 25, with temperatures across the city generally staying below 10 degrees.
Yesterday afternoon was around 3 degrees to 5 degrees warmer than the day before.
The Observatory forecast that the weather will be slightly warmer over the weekend, but temperatures may drop again next week.