Hong Kong has recorded its hottest day of the year so far as urban temperatures climbed to 32.7 degrees Celsius (90.9 degrees Fahrenheit) at the Observatory’s benchmark headquarters weather station.

But the mercury rose even higher in other parts of the city, with 33.8 degrees logged in the New Territories.

The Observatory’s Kowloon headquarters weather station recorded an urban high of 32.7 degrees on Monday afternoon – up on the earlier maximum temperature of 32 degrees on June 13.

And forecasters warned the sizzling temperatures would continue throughout the week.

The weather service predicted the heat would persist overnight, and that the New Territories would experience very hot weather during the day on Tuesday.

Temperatures on Friday, the summer solstice and the longest day of the year, could hit 34 degrees.

“Under the influence of the subtropical ridge, prolonged relatively high temperatures are expected for the rest of this week,” an Observatory spokesman said.

“The public should stay on the alert, drink more water and ensure good air ventilation in indoor environments.”

Walkers protect themselves from the heat in the West Kowloon Cultural District. Photo: Sam Tsang

The mercury level at the Sheung Shui weather station in the New Territories peaked at 33.8 degrees at about 3pm on Monday.

Other parts of the New Territories, such as Yuen Long and Tai Po, logged maximum highs of 33.7 degrees.

Temperatures at the weather station on Tai Mo Shan, Hong Kong’s tallest mountain, reached 23.7 degrees.

The weather station at King’s Park in Yau Tsim Mong, Kowloon, has recorded temperatures higher than 30 degrees seven times this month.

The forecaster issued the first amber signal of the year under the city’s new high temperature warning system last Wednesday.

An amber alert under the three-level alert system, developed last year, is issued when the heat index hits 30 degrees.

It is upgraded to red at 32 degrees and to black at 34 degrees.

The Labour Department’s guidelines recommend that people working outside should rest for between 15 to 45 minutes every hour depending on the risk assessment after a heat alert is issued and take precautions against heatstroke.