Mumbai Sees First Heatwave of 2026 in Early March as Temperatures Hit 38.9°C

The afternoon sun had turned the platforms at Santacruz station into a strip of shimmering metal and concrete. Commuters fanned themselves with newspapers, children clutched water bottles, and a hot, still air hung over Mumbai’s western suburbs. By the time the India Meteorological Department finished its readings on March 5, the suburb’s temperature had climbed to 38.9°C — nearly six degrees above normal — and the city had entered its first heatwave of 2026.

Weather officials and forecasters said the spike, coming in the first week of March rather than closer to April or May, underscored how quickly Mumbai’s hot season is shifting forward and intensifying.

Heatwave threshold met at Santacruz

On March 4, the IMD’s Santacruz observatory recorded a maximum temperature of 38.7°C, described in multiple forecasts as the hottest day of the year so far and roughly 5 to 6°C above the seasonal average for early March. The following day, the maximum in the suburbs nudged up to 38.9°C. Hindustan Times reported that the surge met IMD criteria for declaring a heatwave in Mumbai, calling it the city’s first heatwave of the season.

The IMD issued a yellow alert for north Konkan, including Mumbai, warning of hot and humid conditions on March 4 and 5. By March 5, the agency had also issued what The Economic Times described as the first heatwave warning of the season for Mumbai, Pune, Thane and Palghar, as temperatures along the Konkan belt rose unusually high for early March.

Under IMD norms, a heatwave at coastal stations such as Mumbai is declared when the maximum temperature is at least 37°C and the departure from the long-term normal is 4.5°C to 6.4°C. Private forecaster Skymet Weather summarized the rule as requiring surface temperatures above 37°C with a departure from normal of 4.5°C or more for coastal heatwave conditions.

At Santacruz on March 5, the 38.9°C maximum and a positive anomaly of about 5.9°C met that threshold. In south Mumbai, the Colaba observatory recorded around 36.2°C to 36.4°C—about 3.4°C to 3.5°C above normal, according to figures cited by national dailies.

Why the city heated up

Meteorologists attributed the spike to a familiar combination: hot, dry winds blowing in from inland Maharashtra and a delayed or weakened sea breeze from the Arabian Sea. Normally, sea breeze begins to flow inland by late morning and caps daytime heating near the coast. When it arrives late or is suppressed, land areas such as Santacruz can heat rapidly into the late afternoon.

Those local factors also aligned with a broader seasonal outlook. In its forecast for the March-to-May hot weather season, the IMD had warned that most of India was likely to see above-normal maximum and minimum temperatures, with a higher-than-usual number of heatwave days in several regions, including parts of Maharashtra.

Early timing stands out

The absolute numbers were below Mumbai’s March record — 41.7°C at Santacruz, first set on March 28, 1956 — but the timing of the heatwave drew attention.

Long-term averages put Santacruz’s normal March maximum around 32°C to 33°C, with minimums near 21°C to 22°C. In recent years, however, the city has repeatedly seen March temperatures climb into the high 30s and occasionally near 40°C.

The IMD declared 2022 India’s hottest March since 1901, with Mumbai touching around 39.4°C on multiple days as part of a broader India–Pakistan heatwave. Similar near-40°C March days were documented again in 2023 and 2025, prompting heat advisories and municipal warnings.

What differs in 2026, forecasters say, is not only how hot it got but how early it arrived.

“Usually such temperatures are seen towards the end of March,” Skymet noted in its coverage of the March spike. This year’s 38.7°C and 38.9°C readings in the first week of the month suggest the onset of dangerous heat is creeping forward on the calendar.

What happens next

After peaking on March 4 and 5, Santacruz’s maximum dipped to 34.6°C on March 6 — still about 1.5°C to 2°C above normal for the date, according to reports citing IMD data. The agency shifted its emphasis from “heatwave” back to “hot and humid” conditions and continued a yellow alert into the weekend for Mumbai and neighboring districts.

Daytime temperatures in the mid-30s, combined with elevated night-time minimums around 23°C to 24°C and high humidity, left many residents with little relief after sunset. Coastal cities such as Mumbai often experience a higher heat index — a “feels like” measure combining humidity and temperature — increasing heat stress even when the maximum stays below 40°C.

Health risks in a humid city

Public-health experts have long warned that humid heatwaves in India are linked to higher rates of heat exhaustion, dehydration, and worsening cardiovascular and respiratory illnesses, particularly among older adults, young children and people with preexisting conditions. Those risks are amplified in a city where millions live in dense settlements with limited access to cooling.

Researchers studying Mumbai’s urban heat island effect have documented that built-up, low-lying neighborhoods with sparse tree cover and many metal or asbestos roofs can be several degrees warmer than coastal promenades or parks, especially at night. In these areas, households often lack air conditioning and rely on ceiling fans and cross-ventilation; during episodes of hot, humid weather, indoor temperatures can remain high well into the night.

Outdoor and informal workers — including construction laborers, street vendors, delivery riders, sanitation staff and port workers — are especially exposed, as they spend the hottest hours of the day outside and often lack formal protections such as mandated rest breaks, shade or access to drinking water.

Preparedness and policy questions

The IMD’s heatwave alerts are designed to feed into Heat Action Plans developed by state governments and city administrations in coordination with the National Disaster Management Authority. Maharashtra and Mumbai have adopted such plans in recent years. Typical measures include early public messaging on heat risks, ensuring water availability, adjusting school schedules and bolstering hospital preparedness.

Whether those measures fully activated during this early-March episode remains unclear. Municipal advisories in past years have urged residents to stay hydrated, avoid direct sun in the afternoon and watch for signs of heat stress. But the quick escalation from late-February conditions to near-39°C in the first week of March is testing how early and how forcefully those systems respond.

Some Indian states have begun treating heatwaves as state-specific disasters, allowing for dedicated funding and compensation mechanisms. Labour groups and climate researchers have called for stronger, enforceable standards for workplace heat safety, particularly as climate models project more frequent and intense hot spells across South Asia, including along its coasts.

For now, Mumbai residents are left watching the sky and the forecast, even as ceiling fans spin in homes weeks before the traditional summer vacation period. The IMD has cautioned that above-normal temperatures are likely to persist across much of the country through May, with more heatwave days than average in several regions.

On the platforms at Santacruz, as the evening rush thinned on March 5, the air remained thick and warm. The calendar still read early March, but the city’s first heatwave had already come and gone — an early signal, forecasters say, of the longer and hotter season ahead.