Weather
Paris
The weather in Paris is can be somewhat fickle. Rain is more common than snow throughout the winter. In recent years, Paris has had about 15 snow days a year, while there are only a few oppressively hot days (over 86°F, or 30°C) in summer. Other than the occasional winds and rain, Paris offers some of the most pleasant weather of any capital in Europe, with an average temperature of 53°F (12°C).
As the old song says, Paris is at its best in springtime, even if it is sometimes a little wet. May, June, September and October are also terrific times to visit Paris. The weather's more pleasant than during the heat of summer, the French should be working, and everything is still open and geared up for tourists. In addition, you'll avoid the peak crowds.
Provence
The weather in Provence is distinct from season to season. During Europe’s heaviest tourist season from July to August, Provence is at its warmest. The summer not only brings the sun to Provence’s valleys but also a dry spell. While this arid climate is perfect for cultivating olives and lavender, travelers should remember to stay hydrated.
The temperature in the summer occasionally reaches just over 100°F, but on average temperatures range around 82°F (26°C). Relief from the summer heat comes in the form of a strong wind called the Mistral, which sweeps through the valleys, spreading the aromatic scent of lavender through the air.
The spring and fall are the choice seasons for traveling. Rain showers revitalize the parched earth during these seasons. Also, in the spring the cherry orchards and herbes de provence are in full bloom, and delight the senses. On the coast the winters are moderated by the Mediterranean Sea making the temperature milder. Throughout the hill towns, such as Bonneiux and Ménerbes, there is snowfall during the winter, making it chillier. The average winter temperature is 43°F (6°C).
Florence
The best time to visit Florence is in May, early June, late September and October. Days during those months are usually warm, and quite long. Since most Italians leave their hot cities in the summer, some restaurants might be closed in Florence.
Rome
It's warm all over Italy in summer; it can be very hot in Rome. The high temperatures begin in Rome in May, often lasting until sometime in October. In Rome the weather is warm year-round, averaging 50°F (10°C) in winter. For the most part, it's drier in Italy than in North America, so high temperatures don't seem as bad because the humidity is lower.
In Rome, temperatures can hit the 90s, but nights are cooler and much more comfortable. The average high temperatures in central Italy and Rome are 82°F (28°C) in June, 87°F (31°C) in July, and 86°F (30°C) in August; the average lows are 63°F (17°C) in June and 67°F (19°C) in July and August.
April to June and late September to October are the best months for traveling in Italy—temperatures are usually mild and the crowds aren't quite so intense. Starting in mid-June, the summer rush really picks up, and from July to mid-September the country teems with visitors.
From late October to Easter, most attractions go on shorter winter hours or are closed for renovation. Many hotels and restaurants take a month or two off between November and February, and it can get much colder than you'd expect (it might even snow).