A cool wind from the sea and pre-monsoon rains brought the first signs of respite to southern Pakistan on Wednesday as the death toll from a scorching heat wave climbed to 838 – a high figure even for a nation accustomed to sizzling hot summers. Temperatures in hard-hit Karachi, the country’s largest city and its commercial hub where the overwhelming majority of the deaths were reported, dropped to 34 degrees Celsius , meteorologist Abdur Rasheed said.