The weather in San Francisco is cool to mild throughout the year, with foggy summers and wet winters. The climate is influenced by the cold currents of the Pacific Ocean surrounding the city, which in conflict with the Californian mainland's summer heat, creates foggy conditions that blanket the city during summer and early autumn. This ensures summers (June to August) in San Francisco are cooler than inland California and average high temperatures reach 77°F (25°C). Winters (December to February) are mild during the day, with temperatures seldom dropping below 60°F (16°C) lows, but nights are cold and rain is common. Rain in summer is rare.