▁with ▁w ester ly ▁waves ▁in ▁the ▁upper ▁parts ▁of ▁the ▁country . ▁Trop ical ▁Storm s ▁usually ▁form ▁during ▁the ▁summer ▁months ▁from ▁late ▁April ▁till ▁June ▁and ▁then ▁from ▁late ▁September ▁till ▁November . ▁They ▁affect ▁the ▁coast al ▁local ities ▁of ▁the ▁country . ▁D ust ▁storm s ▁occur ▁during ▁summer ▁months ▁with ▁peak ▁in ▁May ▁and ▁June , ▁They ▁are ▁locally ▁known ▁as ▁And hi . ▁These ▁dust ▁storm s ▁are ▁quite ▁violent . ▁D ust ▁storm s ▁during ▁the ▁early ▁summer ▁indicate ▁the ▁arrival ▁of ▁the ▁mon so ons ▁while ▁dust ▁storm s ▁in ▁the ▁aut umn ▁indicate ▁the ▁arrival ▁of ▁winter . ▁He at ▁waves ▁occur ▁during ▁May ▁and ▁June , ▁especially ▁in ▁southern ▁P un j ab , ▁central ▁Bal och istan ▁and ▁S ind h . ▁Th under st orm s ▁most ▁commonly ▁occur ▁in ▁northern ▁P un j ab , ▁K hy ber ▁Pak ht unk h wa ▁and ▁Az ad ▁K ash mir . ▁Cont inental ▁air ▁prev ails ▁during ▁the ▁period ▁when ▁there ▁is ▁no ▁precip itation ▁in ▁the ▁country . ▁ ▁Pakistan ▁has ▁four ▁seasons : ▁a ▁cool , ▁dry ▁winter ▁from ▁December ▁through ▁February ; ▁a ▁hot , ▁dry ▁spring ▁from ▁March ▁through ▁May ; ▁the ▁summer ▁ra iny ▁season , ▁or ▁south west ▁mon so on ▁period , ▁from ▁June ▁through ▁September ; ▁and ▁the ▁retre ating ▁mon so on ▁period ▁of ▁October ▁and ▁November . ▁The ▁on set ▁and ▁duration ▁of ▁these ▁seasons ▁vary ▁somewhat ▁according ▁to ▁location