Rome enjoys a Mediterranean climate (Köppen climate classification: Csa), with mild, humid winters and warm, dry summers.
Its average annual temperature is above 20 °C (68 °F) during the day and 10 °C (50 °F) at night. In the coldest month – January, the average temperature is 12 °C (54 °F) during the day and 3 °C (37 °F) at night. In the warmest months – July and August, the average temperature is 30 °C (86 °F) during the day and 18 °C (64 °F) at night.
December, January and February are the coldest months, with average temperatures around 12.5 °C (54.5 °F) during the day and 3.6 °C (38.5 °F) at night. Temperatures generally vary between 10 and 15 °C (50 and 59 °F) during the day and between 3 and 5 °C (37 and 41 °F) at night, with colder or warmer spells occurring frequently. Snowfall is rare but not unheard of, with light snow or flurries occurring almost every winter, generally without accumulation, and major snowfalls once every 20 or 25 years (the last one in 2012).
The average relative humidity is 75%, varying from 72% in July to 77% in November. Sea temperatures vary from a low of 13 °C (55 °F) in February and March to a high of 24 °C (75 °F) in
