Florence is situated in the Valley of the River Arno. It is surrounded by hills on three sides. To the north there are the hills of Careggi and Fiesole, to the east Settignano, while to the south there are the hills of Arcetri, Poggio Imperiale, Scandicci and Bellosguardo. To the northwest there is an opening where the neighbouring towns of Sesto Fiorentino and Prato are situated and it in this direction that Florence has moslty expanded. On the hills Florence also grew, but in a restricted manner; they still preserve their small-town ambience or are still dotted with farmland and villas.

Florence is crossed by the River Arno, a river that though navigable in Roman times, is now silted; now only sporting rafts can go up and down and even then only in the tect between Ponte alle Grazie and Ponte Santa Trinita. The characteristic colour of the Arno is brown, due to the amount of mud that is transported by its waters and has little to do, as some would like to claim, with the quality of the water. In fact it is not unusual to see fish in the Arno and even nutrias (Myocastor coypus) can be observed swimming at times.

The Arno forms a basin and drains several rivers and streams, notably the Mugnone, the Ema, the Affrico and the Greve, all of which are either in Florence itself or in its vicinity.

Most of the tributaries of the Arno have been canalised, some as far back as the Middle Ages, while others survived intact till the XX century. The Mugnone, which flowed into the Arno in the vicinity of where Ponte Vecchio now spans the river, has twice been deviated and now joins the Arno at the end of the Parco delle Cascine, where there the famous Monumento all’Indiano stands.

The climate of Florence is Mediterranean (though some would classify it as subtropical), with very hot summers (average minimum and maximum temperatures in July, the hottest month, 66F / 91F) and cold, damp winters (average minimum and maximum temperatures in January, the coldest month 33F and 46F). Due to the protection given to Florence by the surrounding hills, its highest and lowest temperatures are very often the record temperatures in Italy. The hottest it ever was in Florence was 109°F in July 1983, while the lowest was -9F in January 1985.

There are two main rainy seasons: in spring and in autumn, though there is also some rainfall (and occasional snowfall) in winter. Summers are normally dry, but there may be the occasional thunderstorm. This hot and dry period usually finishes at Ferragosto, that is, on 15 August, when the first rains should start.

The Arno is very much influenced by the rain in the surrounding hills, going from a placid river to a stormy mountain torrent in a few days.

There are few entirely natural places in the city, though there are woods on the surrounding hills and there there are a number of villas and farms, giving to the outskirts of the city of a city in a garden, surrounded as it is by olive groves, vineyards and cypresses.

Though Florence seems at first a city of stone, with buildings that come almost to the street, and all built against each other and few gardens are visible, this is a false impression. Anyone who has ever gone by a palazzo when the gate is open will have seen that on the other side, usually beyond a covered passage, there is usually a courtyard and very often a garden inside. Florence seen from the air or from the back window of a house reveals itself as a very green city, but with all these green spaces are secret.

There are however a few parks in the centre of the city, such as Piazza d’Azelio, Piazza Demidov and the Boboli Gardens.

In the Oltrarno, immediately outside the city walls, extensive landscaping took place in the XIX century under the direction of Giuseppe Poggi, resulting in Bobolino and the scenic avenues leading to Piazzale Michelangelo. Other important gardens, all privately owned, are the Giardino della Gherardesca, the Giardino Corsini, the Giardino Torrigiani and the Giardino Bardini.

The is also botanical gardens (Giardino dei Semplici) in Florence and, just outside the city walls, the Parco delle Cascine.

There are also two small, seasonal gardens near Piazzale Michelangelo, the Giardino delle Rose, opened in May and June, and the Giardino dell’Iris, which is only open to the public for three weeks in May.