The best time to visit most of Saudi Arabia is October to April, when temperatures are tolerable and the desert landscape is at its most welcoming. Spring (March–April) is particularly pleasant: daytime temperatures in Riyadh hover around 25°C, the desert can turn green after rains, and the light in the northwest canyon country is extraordinary.
Summer (June–August) is brutal in most of the country. Riyadh regularly hits 45°C. Coastal cities like Jeddah are somewhat cooler but intensely humid. The exception is the Asir region in the southwest, where the mountains around Abha stay comfortably cool — often around 20°C — even in July, with clouds rolling in off the Indian Ocean. If you are visiting in summer, Asir is where you want to be.
Winter (December–February) is mild and comfortable in most places. Desert nights can be cold, dropping near freezing on the central plateau. But the days are clear and sunny, and this is when Saudis themselves head out to camp in the desert.
Hajj and Ramadan
The Hajj pilgrimage draws millions of visitors to Mecca and causes country-wide strain on transport and accommodation for one week each Islamic calendar year (dates shift forward roughly 11 days annually). Non-Muslim visitors will find the country crowded and prices elevated at this time. It is generally not ideal for tourism.
Ramadan changes the rhythm of daily life significantly: restaurants only open after dark, business hours shorten, and eating, drinking, or smoking in public during daylight is off-limits for everyone. Some travelers find the evening atmosphere during Ramadan uniquely vibrant. Others find the daytime constraints difficult. Either way, be respectful of local customs.