Weather Forecast: Autumn of 2026 Starts with Heat, and the First Intense Cold Snap Already Has a Date to Arrive
If you were hoping for that nice, crisp chill right in the first week of autumn, you'll have to hold onto that anticipation a little longer. Autumn 2026 officially started this Friday, March 20, but the weather forecast for the coming days points to a lot of heat and a scenario that's completely different from what we used to see back in the day.
At least, that's what the latest weather maps show. The season of falling leaves will arrive with above-average temperatures across most of the country. You know that famous "cold snap" that was already making an appearance at the end of summer? Well, it's taking a break. For those living in the Southeast and Central-West, for example, you'll still face days where thermometers easily top 30°C, as if summer is stubbornly refusing to leave.
Persistent Heat and Irregular Rainfall
What stands out in this seasonal shift is the irregularity. The weather and climate forecast indicates that rainfall will be poorly distributed. While the South and parts of São Paulo might still see more consistent rain in the first few weeks, the interior of the Northeast and northern Minas Gerais will continue to experience water scarcity. And that's concerning, because it's been a while since we've seen a "neat" rainfall pattern like we used to.
To give you an idea, when we run forecast models on the platforms we use to track wind and pressure, the scenarios show a persistent atmospheric block. In practical terms, this means a stagnant hot air mass, preventing those cold fronts—the ones that usually bring in true autumn weather right away—from moving through.
And the Cold, When Does It Really Arrive?
The big question on everyone's mind: where's the cold? Well, I've been tracking the forecast models and the date is already on our radar. The first intense cold snap of autumn—the kind that makes you pull your coat out of the closet and even enjoy a warm coffee in the late afternoon—is predicted to arrive in the first week of April. More specifically, between the 6th and 9th.
During this period, a polar air mass is expected to drop temperatures in the South and cause a significant thermal shock in the Southeast. But don't expect a gradual change. The trend is for us to go from scorching heat near 35°C straight to 15°C in a matter of hours. This kind of abrupt transition is classic for Brazilian autumn, but this year it promises to be more intense.
- South (RS, SC, PR): Pay extra attention! The turn of the month already starts with a temperature drop. Get your blankets and heavier coats ready for the first week of April. Frost could appear in the highland areas.
- Southeast (SP, RJ, MG, ES): The forecast shows that heat will dominate the final days of March. The cold should only arrive in full force around April 7th or 8th, with that icy wind that cuts right through your clothes.
- Central-West and Northeast: The change will be felt less intensely, but nights will become milder, especially in higher altitude areas like the Chapada Diamantina and the Brasília region.
If there's one thing I've learned following the climate - weather forecast all these years, it's that Brazilian autumn has become a box of surprises. Nothing is what it was ten years ago. We have to keep an eye on constant updates, because this back-and-forth of hot and cold air masses tends to catch everyone off guard.
So, here's the tip: enjoy this last weekend of March with that lingering heat, because coming up soon, that intense cold spell will be knocking at your door. And when it knocks, it won't just be to say hello. It'll be here to stay. The weather for couples? For now, only if it's a love for blankets, because the weather outside is going to be just like that.