Climate
Montevideo has a humid subtropical climate (Köppen Cfa) in a middle latitude, the city experiences the four seasons. It has cool winters (June to August), warm to hot summers (December to February), mild autumns (March to May) and volatile springs (September to November); The climate is characterized by having mild temperatures, without harsh cold or extreme heat. There are numerous thunderstorms but no tropical cyclones. Rainfall is regular and evenly spread throughout the year, reaching around 950 millimeters (37 in).
Winters are generally cool, wet, windy and overcast. The average temperature during this season is just above 10 °C (50 °F). Daytime temperatures are generally between 10 °C (50 °F) and 18 °C (64 °F), and night lows between 3 °C (37 °F) and 10 °C (50 °F). During this season, there are bursts of icy and relatively dry winds of continental polar air masses, giving an unpleasant chilly feeling to the everyday life of the city, with daytime temperatures around or below 8 °C (46 °F) and possible night frosts. These occur few times during winter, with temperatures generally not falling below −2 °C (28 °F) because of the oceanic influence that moderates the temperature; a few kilometres inland, frosts are more common and colder. On the other hand, even in the middle of winter it’s not uncommon to have temperatures above 20 °C (68 °F) for a few days. Rainfall and sleet are a frequent winter occurrence, but snowfall is extremely rare: flurries have been recorded only four times but with no accumulation, the last one on 13 July 1930 during the inaugural match of the World Cup, (the other three snowfalls were in 1850, 1853 and 1917); the alleged 1980 Carrasco snowfall was actually a hailstorm.
Summers are warm-hot and humid, with less wind than other seasons. The average temperature in this season is 23 °C (73 °F). Daytime temperatures are usually between 24 °C (75 °F) and 32 °C (90 °F), while night lows between 14 °C (57 °F) and 22 °C (72 °F). During this season, a moderate wind often blows from the sea in the evenings which has a pleasant cooling effect on the city, in contrast to the more severe summer heat of nearby cities like Buenos Aires. Heat waves come with the north winds, which bring humid and hot air masses from the tropical interior of the continent; temperatures can rise above 35 °C (95 °F). These warm periods are usually followed by thunderstorms, generated by cold fronts from the southwest that lowers temperatures considerably. This phenomenon is regional, and can occur several times all year long.
The autumn in Montevideo is quite pleasant and not so unstable. Daytime temperatures are in general around 20 °C (68 °F) and nights around 10 °C (50 °F). Spring average temperatures are very similar to the autumn, but the weather in that season tends to be more windy and volatile, with more dramatic changes in a short period of time.
Montevideo has an annual average temperature of 16.7 °C (62.1 °F). The lowest recorded temperature is −5.6 °C (21.9 °F) while the highest is 42.8 °C (109.0 °F).
