By early afternoon, temperatures in parts of the national capital region goes around 40 to 42 degrees Celsius, and the India Meteorological Department has formally issued a heatwave alert.
April is doing what April does in the plains of north India: it is heating up fast. But this year, the IMD has flagged that the summer of 2026 could be particularly severe across a wide geography. If you live or travel anywhere from Delhi-NCR to coastal Gujarat, the warning is worth paying attention to.
Today's Weather at a Glance (April 21, 2026)
Delhi-NCR
- Maximum temperature expected: 40–42°C
- Minimum temperature (last recorded): 22–24°C
- Sky condition: Clear
- Humidity: Low-to-moderate (dry heat)
- IMD alert: Heatwave alert issued for Delhi and NCR
- Areas of concern: Noida, Greater Noida, Ghaziabad under heatwave conditions from April 20–22. Haryana and Chandigarh under similar alert from April 21–23.
- Nights are also unusually warm, increasing overall discomfort.
Other Major Cities Today
- Mumbai: Partly cloudy, 35–37°C, high humidity. Uncomfortable but no heatwave alert.
- Bengaluru: 32–34°C, some cloud cover, relatively milder.
- Chennai: 36–38°C, humid, coastal heat.
- Kolkata: 37–39°C, humid. Pre-monsoon thunderstorms possible in the eastern region later in the week.
- Hyderabad: 39–40°C, dry. Heatwave-like conditions.
- Ahmedabad: 40–41°C. Gujarat is among the IMD-flagged zones for higher-than-normal heatwave days in 2026.
- Jaipur / Rajasthan: 41–43°C. Hottest region outside the coast.
What Is a Heatwave, By IMD's Definition?
The India Meteorological Department defines a heatwave as:
- When maximum temperature hits 40°C or more in plain areas, OR
- When maximum temperature is at least 4.5°C above normal for that location and season
A "severe heatwave" is declared when the departure from normal is 6.5°C or more, or when the absolute maximum crosses 47°C.
Today, Delhi is at the lower end of heatwave territory — 40–42°C — which meets the threshold but is not yet in severe territory. That said, temperatures will feel worse than the number suggests when you factor in direct sun exposure and low humidity drying out the body faster.
IMD's Summer 2026 Warning: What the Big Picture Looks Like
The IMD Director General, Mrutyunjay Mohapatra, made a significant statement ahead of the season: several parts of India will have a higher-than-normal number of heatwave days in 2026. The regions flagged include:
- Northern Indo-Gangetic plains (Delhi, UP, Bihar, Haryana, Punjab)
- Eastern coastal states (Odisha, Andhra Pradesh coastal areas)
- Gujarat and Maharashtra
Even regions that do not technically qualify for heatwave classification may see temperatures exceeding 40°C, Mohapatra noted. In practical terms, that means a wide belt of India will experience dangerous heat this summer.
The IMD chief also mentioned an important outreach note: in 2025, associations of rickshaw pullers, street vendors, and domestic workers in Delhi approached the weather department directly and asked for advance heat forecasts. IMD responded by providing information through WhatsApp to their association secretaries, who then passed it on to members. This is the kind of granular, last-mile communication that saves lives.
Relief: When Is It Coming?
For Delhi-NCR, temperatures are expected to stay in the 40–42°C range through April 22–23. Some minor relief — a dip of 2–4°C — may come from a Western Disturbance expected to bring patchy cloud cover and possibly a dust storm by the weekend. But sustained relief will not arrive until the pre-monsoon thunderstorm season begins in earnest in May.
The southwest monsoon typically reaches Kerala by early June and Delhi by late June or early July. There is no IMD announcement yet on early monsoon arrival forecasts for 2026.
Also Read: India Weather Today, April 9: The Last Day of Pre-Monsoon Relief
The Human Cost of Heat
India has had some sobering experiences with heat-related deaths in recent years. The elderly, the very young, outdoor workers — daily wage labourers, construction workers, farmers — and people without access to fans or air conditioning are the most vulnerable.
Heat exhaustion and heatstroke are medical emergencies. Heat exhaustion presents as heavy sweating, weakness, cold or pale skin, and a fast but weak pulse. Heatstroke — the more dangerous condition — is when body temperature crosses 40°C, the person stops sweating, and confusion or unconsciousness sets in. This requires immediate emergency care.
Hospitals in Delhi and NCR cities typically report a rise in heat-related emergency admissions from mid-April through June. Children and infants are particularly at risk because their thermoregulation systems are less mature.
Air Quality Note
Delhi's air quality, while a lesser concern in summer compared to winter, is still affected by dust and particulate matter during heatwaves. Strong dry winds from the northwest carry dust from Rajasthan and the Thar Desert. On days with heatwaves, the AQI can cross 200 — into the "poor" category — even without the winter smog.