Dhahran’s climate is characterized by extremely hot, humid summers, and cool winters. Temperatures can rise to more than 50 °C (120 °F) in the summer, coupled with extreme humidity (85-100 per cent), given the city’s proximity to the Persian Gulf. In winter, the temperature rarely falls below 2 °C (35.6 °F) or 3 °C (37.4 °F), being the lowest ever recorded -0.5 °C in January 1964, with rain falling mostly between the months of November and May. The Shamal winds usually blow across the city in the early months of the summer, bringing dust storms that can reduce visibility to a few metres. These winds can last for up to six months.
On July 8, 2003, the dewpoint was 35 °C (95 °F) while the temperature was 42 °C (108 °F), resulting in a heat index of 78 °C (172 °F)