Rain is likely to begin in Karachi from the night of April 1, with the Pakistan Meteorological Department (PMD) saying chances of showers will be higher on April 2 when a westerly weather system enters Balochistan via Iran.
The Met Office said there would also continue to be a chance of rain in Karachi on April 3, while rainfall in some areas could reach 50 mm or more.
It warned that strong winds may also accompany the system, with wind speeds likely to reach 50 kilometers per hour or more.
According to the department, the weather system may continue to affect the country until April 4.
In a new statement issued on Monday, the PMD warned of widespread rain, thunderstorms and strong winds over large parts of the country from April 1 to 4 as a westerly wave moves into southwestern Balochistan before gradually spreading to almost all provinces over the following days.
Sindh is expected to be among the last affected provinces, with Karachi, Hyderabad, Sukkur, Larkana and several other cities likely to receive rain, thundershowers and isolated hailstorms from April 2 to April 4.
The Met Office warned of serious secondary hazards during the period, saying windstorms and lightning could damage weak structures, electricity infrastructure, billboards and solar panels, while standing crops in Sindh and other provinces could also be at risk from hail and strong winds.
It added that daytime temperatures are expected to drop noticeably across the country during the period and advised the public, tourists and travelers to exercise caution and avoid non-essential travel.
The PMD said the weather system is expected to persist beyond April 4 and an updated advisory will be issued in due course.
All concerned authorities have been asked to remain alert and take necessary measures to prevent any untoward situation during the forecast period, the department said.
