Why go
Weather affects the shape of a Paris day more than extreme conditions do. The city can move quickly from sun to showers, and spring or autumn can bring a warm afternoon followed by a fresh evening. Summer heat does occur, while winter is generally cool with limited sunshine and occasional frost or snow.
The full story
Paris has an oceanic climate influenced by the North Atlantic, so rain is spread across the year rather than confined to one season. Summer is often warm and pleasant, but heatwaves can make exposed walks and upper-floor rooms tiring. Spring and autumn are especially variable: a mild day may end with a noticeably cooler evening, and abrupt showers are possible. Winter days are usually cool and daylight can feel scarce, though prolonged severe cold is unusual. Snow falls at times but does not often remain on the ground. This pattern rewards flexible planning. Keep an indoor museum, church or covered passage in reserve when building a walking day, and carry a light rain layer outside the warmest months. For a specific visit, check the forecast close to departure rather than relying on a seasonal expectation.