Climatic map of the Province of Río Negro, Argentina
The climate of the province is temperate at low elevations, and very cold in the higher Andean peaks.
Temperature:
The mean annual temperatures in the province are relatively cold for its latitude owing to the marine currents to the east and higher altitude to the west. Mean annual temperatures in the province can vary, depending on altitude and distance from the sea. The northern parts of the province are the warmest, with a mean annual temperature of more than 15 °C while the coldest areas are found in the Cordillera where the mean annual temperatures are less than 10 °C. At the highest peaks, the mean annual temperature is less than freezing. Summer temperatures can exceed 40 °C although the mean January temperatures range from 20 to 24 °C. In contrast, the Andean region has milder summers with mean January temperatures of 15 °C or less, depending on the altitude. In July, mean temperatures range from 7 to 8 °C on the coast in the north to around 2 to 3 °C in the central plateau.
Humidity and precipitation:
Relative humidity is lower in the central plateau where it average 50%. Along the coastal regions, humidity is higher with a mean annual humidity of 60% while the Andean region has the highest humidity with an average annual humidity exceeding 65% due to the lower temperatures there. In all locations, humidity is lower in the summer and higher in the winter owing to the higher temperatures in the summer.
The Andes block most of the moisture from the Pacific Ocean from coming in, causing it to release most of the precipitation on its western slopes and as such, most of the province is dry, with a mean annual precipitation around 200 millimetres. Coastal areas and northern parts of the province receive a slightly higher precipitation, where it can average above 300 millimetres a year. The Andean region receives the most precipitation with areas receiving a mean annual precipitation of 200 to 1,000 millimetres in which the precipitation gradient is very strong and increases westwards. In some places, precipitation can exceed 3,000 millimetres a year. Most of the Andean region has a rainfall pattern that is Mediterranean like, similar to Central Chile in which most of the precipitation falls during the winter months and summers are dry.
Wind and sunshine:
One dominant characteristic of the climate is the strong winds that are observed throughout the province. Summers tend to be windier than winters. Winds coming from the west, southwest and northwest are common, occurring 50% of the time (60% if calm winds are not included). There is some tendency for the winds to come from the east, particularly on the coastal regions when sea breezes from the east can occur when westerly winds are weak, which can be felt up to 10 kilometres from the coast. The mean wind speed throughout the province varies with the northern parts having the lowest wind speeds while the highest altitude areas being the windiest. Except for the northern parts of the province, mean annual wind speeds exceed 4 metres per second.
Cloud cover varies throughout the province, ranging from more than 60% in the Andean region to about 40% in the coastal areas. The central plateaus have intermediate amounts of cloud cover between these 2 regions. As such, the Andean region is cloudier than the rest of the province. Sunshine ranges from 10?11 hours of sunshine/day in January to about 5 hours of sunshine/day (less cloudier areas) to less than 3 hours of sunshine/day (more cloudier areas) in July.