A good question, indeed! Unfortunately, seasonal weather is not consistent from year to year, and even today's forecast for tomorrow often turns out to be wrong. There is nothing unusual about having lunch on the Cours Saleya, with a tee-shirt on, in February, for Carnival, and wearing a jumper, on a summer evening, whilst attending the open air concerts in the Cimiez Gardens. The following guide is based on averages, which can hide a multitude of sins! Please don't sue us if we're wrong!
Nice enjoys over 3,000 hours of sunshine annually. With an average of only 4 rainy days a month throughout the year (London 12, Manchester 15!), a temperature that rarely goes above 90F in summer or below 40F in winter, it is an all-year destination as popular (and as lively) in winter as in summer. It does snow about once every ten years, but the last time was February 2005, so you should be OK until 2015!
Springtime temperatures are usually shirt-sleeve warm during the day and cool enough for light jackets at night. Weather often changes day-by-day, with a mixture of clear, sunny days interspersed with two or three days of partial clouds and some rain. When the rain does come, it comes in torrents, but usually briefly.
Summers are hot. But this isn't the day-and-night heat and humidity of the Southern United States. Even on the coast here it cools off at night. The air is often hazy, especially in the mornings. As the morning warms up, the haze burns off somewhat, especially as you get higher up into the hills. Where we are, there is nearly always a gentle cooling breeze.
Autumn days are usually clear and brisk - except for occasional stormy days - an excellent time to see the sites without the summer haze, and with fewer people.
Winters are mild compared with Northern Europe and the USA, and the outdoor life is still king. Although there are some cold days - particularly when it is windy - most of the time you are still able to eat lunch outside even in mid winter. Don't try it in the evenings, though!
Click for Nice weather information - access to a number of weather forecasting sites plus historical data.