Roughly speaking, Pakistan has three seasons: cool (autumn-winter, October through February), hot (spring, March through June) and wet (summer, July through September). There are, however, big regional variations. In all Seasons, the ‘continental’ climate can mean big day-night temperature differences.
In the south, autumn-winter brings bright, dry days and cool nights, while the northern mountains get lots of drizzle or snow, cold days and bitter nights. Spring means dust and even in lower mountain elevation like Gilgit’s, but pleasant temperatures northwards.
In summer, the tail end of the south-west monsoon dumps steady rain across the central
And eastern plains and as far north as Swat, Kohistan, the Kaghan Valley and Azad Kashmir – interspersed with heat and heavy, sauna-like humidity. But the monsoon doesn’t reach much further and, except for random thunderstorms, this is a good time to go north (trekkers should also refer to the Trekking chapter.
In Sind and southern Punjab, spring temperature may reach 45c or more, with the un- acclimatized risking heat exhaustion; even nights can be miserable. The monsoon come in July-August, though Karachi and southern Sind get little rain, just humidity.
Autumn-winter in the Peshawar –Rawalpindi-Lahore belt means crisp days and cold nights, with occasional rain from the west, the monsoon come from late July to September, later in Peshawar and not at all in Baluchistan.
Winter in the northern parts of the NWFP, Northern Areas and Azad Jammu & Kashmir is long, snowy and cold. Most high passes and many roads are blocked by snow. Rain come from the west in random spring and summer storms. The best weather is in May-June and September- October.