The highest temperature recorded in the port city was in April was 44.4 degrees Celsius on April 14, 1947, and the mercury never rose as high as 43.6 degrees Celsius in the city until Saturday in the month of April, The News International reported citing Sardar Sarfraz, the chief meteorological officer of Sindh province.

The Pakistan Meteorological Department (PMD) said that the current weather conditions had developed due to the influence of dry continental air after a westerly disturbance in Pakistan.

"...A weak western disturbance is on the horizon. It will affect the upper parts of the country, but when it passes, it will bring more hot days for the southern parts, including Karachi," said Sarfraz.

Meanwhile, the PMD issued a warning that the first heatwave of the current season is likely to hit several parts of the country this week, Geo News reported.

Mainly hot and dry weather was expected during the week due to which heatwave conditions were likely to prevail in most plain areas of the country, according to the PMD.

The Sindh government has directed authorities to take necessary precautions to avert loss of life.