April, May, September and October are the best months. Highs run from 20 to 24 degrees in spring and from 22 to 27 in early autumn, and the summer crowds have not arrived or have thinned out. June, July and August are the busiest and the hottest, with highs of 29 to 32 degrees. November and December have the most rain days, about ten each, which suits a trip built around museums.
Best months: April to May and September to October
Highs climb from 16 degrees in March to 24 in May, and rain falls on seven to nine days a month. Easter weeks are busy. Outside them the streets are easier to walk than in summer.
What to wear: Pack layers, a light waterproof and shoes that cope with wet cobbles.
Summer
17 to 31 °C · about 4 rainy days a month
Highs run from 29 degrees in June to 32 in July and August, with warm nights near 18. Rain falls on three to five days a month, usually as short storms. The centre is crowded and the stone streets hold the heat well into the evening.
What to wear: Wear light cotton, a hat and flat shoes, and carry a scarf for churches that ask for covered shoulders and knees.
Autumn
11 to 22 °C · about 8 rainy days a month
September is still warm at 27 degrees, October drops to 22 and November to 16. October and November are the wetter months, with nine or ten rain days each.
What to wear: Bring a jacket and a compact umbrella, and add a warmer layer from late October.
Winter
3 to 12 °C · about 8 rainy days a month
Highs sit around 11 to 13 degrees and nights average 2 or 3. Rain falls on seven to ten days a month. The museums are quieter, but daylight is short and the Boboli Gardens close early.
What to wear: Wear a warm coat, a scarf and waterproof shoes, and dress in layers because churches are not always well heated.
If it rains
Florence has enough indoor sights to fill a wet day. The Uffizi, the Accademia, the Pitti Palace, the Bargello, the Medici Chapels, Santa Maria Novella and Santa Croce are all under cover, and the Mercato Centrale works as a dry lunch stop. Keep Piazzale Michelangelo and the Boboli Gardens for a dry day. The Palazzo Vecchio tower closes in rain.
From June to August highs reach 29 to 32 degrees, and the stone streets hold the heat into the evening. Do the outdoor stops early or after 18:00, and keep the museums and churches for the middle of the day. Piazzale Michelangelo is an open terrace with little cover, so go near sunset and carry water.