Uruguay's climate is relatively mild. Located entirely within the temperate zone Uruguay has a climate that is fairly uniform nationwide. Seasonal variations are pronounced, but extremes in temperature are rare. As would be expected by its abundance of water, high humidity and fog are common. The absence of mountains, which act as weather barriers, makes all locations vulnerable to high winds and rapid changes in weather as fronts or storms sweep across the country. Both summer and winter weather may vary from day to day with the passing of storm fronts where a hot northerly wind may occasionally be followed by a cold wind (pampero) from the Argentine Pampas.
Uruguay has a largely uniform temperature throughout the year, summer being tempered by winds off the Atlantic, and severe cold in winter is unknown. The heaviest precipitation occurs during the autumn months, although more frequent rainy spells occur in winter. The mean annual precipitation is generally greater than 40 inches (1,000 mm), decreasing with distance from the sea coast, and is relatively evenly distributed throughout the year.
The average temperature for the mid-winter month of July varies from 12 °C (54 °F) at Salto in the northern interior to 9 °C (48 °F) at Montevideo in the south. The midsummer month of January varies from a warm average of 26 °C (79 °F) at Salto to 22 °C (72 °F) at Montevideo. National extreme temperatures at sea level are, Paysandú city 44 °C (111 °F) (20 January 1943) and Melo city −11 °C (12.2 °F) (14 June 1967)