Spring 2026 Begins This Tuesday With a Strong El Niño; Here’s What Changes in Greater ABC

Spring 2026 begins in the Southern Hemisphere this Tuesday (September 22), at exactly 9:05 pm Brasilia time. The moment marks the spring equinox, when the Sun crosses the celestial equator and day and night are approximately equal in length across the planet.

What an equinox is

According to researcher Josina Nascimento, of Brazil’s National Observatory, an equinox is the moment “when the Sun crosses the celestial equator, the extension of Earth’s equator, moving from the Northern to the Southern Hemisphere.” The seasons result from the tilt of Earth’s rotational axis combined with its orbital position around the Sun — they are not defined by sunrise time or by temperature, but by this precise point in Earth’s orbit.

A strong El Niño could make this the hottest spring on record

The season arrives under the influence of what forecasters consider an exceptionally strong El Niño. According to meteorologist Juliana Hermsdorff, of Squitter, NOAA (the US weather agency) estimates a probability above 90% of a very intense event in September, with a 75% chance that, between October and December, it will surpass the intensity of every episode recorded since 1950.

Forecasts point to heavy rain and temperatures up to 2°C (3.6°F) above average between September and October, with highs that could reach 30°C (86°F) in the Greater ABC region and across most of Southeast Brazil. Meteorologist Fabio Pinto da Rocha, of INPE (Brazil’s national space research institute), also projects heat waves, with high afternoon temperatures and low relative humidity — recommending sun protection and hydration, especially for the elderly and children.

Greater ABC prepares for heat and heavy rain

Local governments in the region are already mobilizing. Santo Andre is installing hydration stations offering free drinking water in high-traffic areas and plans to expand green infrastructure and create heat refuges. Sao Caetano has directed primary care teams to work more closely in areas identified as heat islands. Diadema’s Civil Defense maintains ongoing monitoring of risk areas, and Maua is reviewing medication stockpiles to prepare for potential logistical disruptions. In Ribeirao Pires, the contingency plan is in its final stages and is expected to be presented by the end of September.

At the national level, Brazil’s Ministry of Health launched the AdaptaSUS program to prepare the public health system for extreme climate events. According to Health Minister Alexandre Padilha, data from the Fiocruz research institute shows that 120,000 people have died in Brazil over the past 20 years due to rising average temperatures — underscoring that the climate crisis is also a public health crisis.