The maximum temperature was 24.6 degrees C against 33.5 degrees on Thursday.
The night’s minimum temperature was 22.4 degrees and the humidity on Friday morning and evening was 96 per cent.
The rain was caused by the first monsoon low pressure whose effects reached Pakistan. It was light because it was not supported by any westerly wave or moisture from the Bay of Bengal or the Arabian sea, Chief Meteorologist Shaukat Ali Awan said.
He said the outer peripheral clouds of the low pressure over Delhi, India, gave light rain up to Islamabad and over the catchments of the eastern rivers Ravi, Chenab, Sutlej and Jhelum.
Mr Awan said the system gave 220mm of rain in Delhi and 80mm in Agra.
In Lahore, the almost evenly spread light rain started at around 7am and was continuing till in the evening.
By 6pm the local Met office had recorded 10mm of rain at the airport, 11mm at Shahdara and 9mm at its Jail Road observatory.
It also reported rain in Sialkot 30mm, Rawlakot and Kotli 2mm each.
The Met Office has forecast more rain in Lahore and many other cities in the Punjab, the NWFP and the Northern Areas during the next 24 hours.