Sharjah has the same climate as the rest of the UAE: brutally hot from June through September (40°C+, very humid), and warm and pleasant from November through April. Winter (December–February) is the best time — temperatures in the mid-20s, low humidity, and clear skies. During Ramadan the city's already conservative atmosphere becomes more strictly observed; many restaurants close during daylight hours and entertainment venues shut entirely.
Spring (March–April) and autumn (October–November) are also comfortable. Visiting in summer is feasible if you stay in air-conditioned spaces, but the Heritage Area's outdoor walking circuit becomes genuinely unpleasant in the heat.