Cold wave in South America: the polar cold extends to Uruguay

Cold wave marks the beginning of spring in the south of the continent

Despite the change of season, the weather in the Southern Hemisphere is refusing to abandon its winter-like characteristics. This Monday, at 3:19 p.m., spring officially began, but the arrival of a cold wave from southern Brazil is marking an atypical start to the season. According to the Brazilian Meteorological Service Metsul , the phenomenon will significantly affect several states in southern Brazil and could have specific effects in northern and northeastern Uruguay.

A polar air mass has begun advancing from the state of Rio Grande do Sul, moving toward southeastern and central-western Brazil. It is also expected to impact densely populated areas such as São Paulo, Rio de Janeiro, and Minas Gerais, where high temperatures were recorded over the weekend but will now face a marked drop in temperature.

Winter conditions in late September

According to Metsul, while it's not unusual for spring to begin with remnants of winter conditions, this cold snap stands out for its intensity and persistence. " Polar air masses can still reach Brazil at the beginning of the flowering season, but these events are generally brief. In this case, the duration and geographic extent are greater," the agency stated.

Weather models predict minimum temperatures below 5°C in mountainous areas of southern Brazil, and even near 0°C or below in high-altitude areas of Santa Catarina and Paraná , especially between Thursday, September 25 and Friday, September 26. Late frosts , an unusual phenomenon at this time of year.

In Porto Alegre , the capital of Rio Grande do Sul, lows will range between 8°C and 12°C throughout the week. Meanwhile, in cities like São Paulo and Rio de Janeiro , after a hot weekend with highs above 30°C, a sharp drop in temperatures, rain, and noticeably cool afternoons are expected to close out the month.

Possible effects in Uruguay: cold in the north and rural frosts

In Uruguay, the phenomenon could be felt most strongly in the northern and northeastern departments, such as Artigas, Rivera, Cerro Largo, and Tacuarembó , due to their proximity to the hardest- hit areas of southern Brazil . Projections do not indicate widespread frost, but there is a risk of isolated frost in rural areas , especially in the early hours of Thursday and Friday.

Uruguayan meteorologist Mario Bidegain explained in a recent interview that "these types of situations are not uncommon in spring, when the continent still receives cold air from the south . But what's surprising this time is the temperature range and duration of the event."

moderate drop is expected in the rest of Uruguay , with cool mornings and mild afternoons, although below average temperatures for this time of year. Southerly winds are possible , reinforcing the low winds during the early hours of the day.

Concern in the agricultural sector and warning for the vulnerable population

Episodes of intense cold weather out of season can have consequences for agriculture, especially for cold-sensitive or early-flowering crops. In Brazil, alerts have been issued for producers of fruits, vegetables, and ornamental flowers due to the risk of frost damage. In Uruguay, although the impact is expected to be less severe, the INIA (National Institute of Agricultural Research) and other agricultural organizations are monitoring the situation.

The most vulnerable population—elderly adults, children, and homeless people—are also warned to take precautions against exposure to the cold, as these abrupt temperature changes can lead to respiratory conditions.