Early-Season Heat Arrives With a Jolt in Mumbai and South Africa’s Cape

The school day in Mumbai was barely half over when the ceiling fans started to feel pointless.

By early afternoon on March 5, the main weather station at Santacruz had climbed to nearly 39 degrees Celsius (102 Fahrenheit), almost six degrees above what is typical for early March. In some neighborhoods, automatic stations would later show readings above 41 and 42 degrees as the city moved through the first week of the month. Teachers cut back outdoor activities, office workers shifted errands to the evening and street vendors sought slivers of shade that did little to blunt the heat.

Six thousand kilometers away, residents of South Africa’s Western Cape were watching a similar forecast darken. On March 8, the South African Weather Service warned that “very hot to extremely hot temperatures (36°C to 42°C)” were expected over parts of the Northern and Western Cape from March 9 to 13, driven by a strong high-pressure system aloft and hot, downslope winds. By Monday morning, local radio bulletins were advising people in the Cape interior to stay indoors during the hottest hours.

The two events, unfolding in the first half of March in opposite hemispheres, were driven by different weather systems. But together they illustrated a shared trend scientists and forecasters have been warning about: extreme heat arriving earlier in the season, lasting longer and hitting hardest in urban regions least equipped to cope.

Mumbai’s early-March heatwave

In India, the India Meteorological Department (IMD) confirmed that Mumbai entered heatwave conditions in the first week of March. Santacruz, the city’s primary suburban observatory, recorded a maximum of about 38.9°C on March 5—roughly 5.9 to 6°C above the long-term normal for that date. The agency issued a yellow heatwave warning for the city and surrounding districts including Thane, Raigad and Palghar.

By March 9, the heat had intensified. Local instruments at Ram Mandir in the western suburbs registered 42.5°C, while Vikhroli in the eastern suburbs hit 41.7°C. Santacruz reached 38.4°C, around six degrees above normal; the coastal Colaba observatory measured 35.9°C, nearly five degrees above its March average.

“Daytime temperature at Ram Mandir touched a whopping 42.5 degrees Celsius,” the regional meteorological center said in a bulletin summarizing conditions that Monday, noting that departures from normal at key stations met the criteria for a heatwave.

Under IMD’s definition for the plains, a heatwave is declared when the maximum reaches at least 40°C and is 4.5 to 6.4°C above normal, or when it hits 45°C regardless of average values. A severe heatwave is logged when the departure is 6.5°C or more.

On March 10, as temperatures remained elevated across the metropolis, IMD upgraded parts of the Mumbai region to an orange alert. The designation indicates heatwave-like conditions with a “moderate to high likelihood of heat illness symptoms in people exposed to the sun for prolonged periods,” the agency has said in similar advisories.

“This is an unusually aggressive start to the hot season for coastal Maharashtra,” IMD scientist Sushma Nair told local media, attributing the spike to a synoptic pattern that steered hot, dry air from the interior toward the coast and suppressed cloud cover.

Mumbai is no stranger to sweltering pre-monsoon months. Its climate, classified as tropical wet and dry, typically sees March as a transition period before the more intense heat of April and May. Climatological records show an average maximum of about 32.7°C in March at Santacruz. The station’s all-time March high, 41.7°C, was recorded on March 28, 1956.

What stood out in 2026 was not that every reading set a new absolute record, but that temperatures associated with late March or April arrived in the first 10 days of the month and persisted in patches across the city and surrounding districts.

The early spike came after an unusually warm winter. IMD’s seasonal report for February ranked it among India’s hottest on record, with one of the highest average minimum and mean temperatures since 1901. In a press statement issued Feb. 28, the agency warned that “above-normal number of heatwave days are likely over most parts of northwest India and adjoining areas of central and west-central India during March to May 2026,” explicitly including Maharashtra.

On the ground, the heat pushed up electricity demand as residents relied more heavily on air conditioners and fans. Utilities prepared for high pre-monsoon loads. Public health departments repeated standard advice: avoid going out in the afternoon, drink more water, use oral rehydration solutions, and pay particular attention to older adults, children and outdoor workers.

Conditions were most punishing in the city’s densely built, low-income neighborhoods, where homes are often made of metal sheets or poorly ventilated concrete and where access to cooling and reliable water supplies is limited. Urban planners and health experts have long warned that the city’s heat-island effect—where concrete and asphalt trap warmth overnight—magnifies risk for residents who already face other vulnerabilities.

Western Cape braces for “extremely hot” conditions

On the southern tip of Africa, a different kind of heatwave was taking shape.

On March 8, the South African Weather Service (SAWS) issued a warning for parts of the Northern Cape and the western interior of the Western Cape, with the heatwave expected to persist from Monday, March 9, through Friday, March 13. The advisory was later extended to parts of the Eastern Cape.

“Very hot to extremely hot conditions (36°C to 42°C) are expected across the coastal areas and adjacent interior of the Northern Cape and the western parts of the Western Cape,” SAWS said in a public statement. “The highest temperatures will occur on Tuesday and Wednesday.”

Meteorologists tied the event to a strong upper-air high-pressure system anchored over western South Africa. “The air in upper-air high-pressure systems sinks and warms as it descends, leading to higher temperatures at the surface,” the agency explained, adding that offshore “berg winds”—downslope flows from the interior to the coast—would further elevate temperatures and suppress moisture along the west coast and interior valleys.

March marks late summer and early autumn in the Western Cape. In Cape Town, long-term climate data indicate an average maximum of about 25 to 26°C in March, with cooler nights. Heatwaves with inland readings in the upper 30s and low 40s are not unprecedented, especially in the Little Karoo and other interior basins, but they are considered high-impact events.

During the 2026 episode, forecasts showed Cape Town’s central areas reaching the low to mid-30s, while inland towns in the interior Western Cape and Northern Cape were projected to climb into the upper 30s or low 40s. Local reports emphasized that the most extreme heat would occur away from the immediate coast, even as the metropolitan region experienced days that were far hotter than usual for the time of year.

Health and disaster risk officials urged residents to take precautions similar to those in India: limit outdoor activity between noon and 3 p.m., drink water regularly, wear light clothing, and never leave children or animals in parked cars. Guidance from the City of Cape Town notes that heatwaves most often affect the region between December and early March, with temperatures in inland areas sometimes reaching 40°C during bergwind events.

The heat came on top of longer-term concerns about water security and electricity reliability. South Africa’s power system has struggled with recurring outages in recent years because of capacity shortfalls and maintenance problems, leading to scheduled load-shedding. High temperatures can increase demand for cooling while also adding stress to some power infrastructure. Prolonged hot, dry conditions also raise the risk of wildfires in the Western and Northern Cape, where vegetation is already adapted to burn.

As in Mumbai, exposure to extreme heat in the Cape is uneven. Informal settlements and township neighborhoods, many featuring small homes built from corrugated metal, can become significantly hotter than leafier, wealthier suburbs. Farmworkers and construction crews have limited scope to avoid outdoor labor, even when heat alerts are in effect.

A shared trend: heat earlier, longer and more unequal

Scientists say such events align with a broader pattern. Global assessments have identified South Asia and southern Africa as regions where extreme heat is intensifying faster than the global average, especially when humidity is factored in. Urban coastal areas face overlapping risks from heat, sea-level rise and strained infrastructure.

In both India and South Africa, meteorological agencies have moved in recent years from simple temperature forecasts toward impact-based warnings that attempt to spell out expected effects on health, infrastructure and livelihoods. The goal is to give local governments and communities clearer triggers for action, such as changing school schedules, opening cooling centers, deploying water tankers or providing extra shade and rest breaks for outdoor workers.

The March 2026 heatwaves showed that those forecasts can be accurate, but they also underscored how difficult it remains to turn them into protection on the ground.

As Mumbai looks toward another pre-monsoon season and the Western Cape approaches its next summer, both regions are refining climate plans that refer explicitly to heat stress: more trees and reflective roofs in crowded neighborhoods, better mapping of vulnerable populations, improved coordination between forecasters and health services. The question, forecasters and planners say, is not whether another early-season heatwave will come, but how ready cities will be when it does.