Jeddah, Saudi Arabia's second city and main Red Sea port, sits on the western coast in the Hejaz region, on a low coastal plain backed by mountains inland, at approximately 21.54°N, 39.19°E. It has a hot desert climate (Köppen BWh) that, unlike the interior, is hot even in winter and made humid year-round by the Red Sea, so its heat is sultry rather than dry.

Summer is long and very hot, with a daily average above 30°C from May to October and highs typically around 38–40°C. The combination of heat and Red Sea humidity makes the summer feel oppressive, and when the wind blows in off the interior it can push temperatures toward 47–48°C — the country's record of about 52°C was set nearby in 2010 — while raising dust storms. The sea stays very warm, and nights offer little relief.

Winter, from December to February, is warm and pleasant rather than cool, with January the coolest month — average highs around 29–30°C and mild nights near 19–20°C, though rare cold air from the north can occasionally drop nights to around 15°C or below. This is comfortably the most comfortable season, with warm, sunny days ideal for the coast, and the Red Sea warm enough for swimming year-round.

Jeddah is extremely dry, receiving only around 50–60 mm of rain a year, almost all of it falling between November and March; the summer is effectively rainless. What rain comes can arrive as sudden, intense thunderstorms, and because the low-lying city has limited drainage, these downpours have caused deadly flash floods, as in November 2009. Live rainfall, humidity, and pressure readings for the city are shown in the panels above.

Jeddah's defining weather trait is the pairing of intense heat with Red Sea humidity, which keeps its summers sultry and its winters warm, quite unlike the dry heat of inland Riyadh. As the gateway city for pilgrims travelling to nearby Mecca, its climate shapes the experience of the Hajj, and its exposure to rare but violent flash floods is its most serious weather hazard.

To follow any single measurement in Jeddah more closely, use our live instruments: the online barometer for atmospheric pressure, the thermometer for temperature, the hygrometer for humidity, the anemometer for wind speed, the wind vane for wind direction, and the rain gauge for rainfall.