TL;DR
- MD heatwave alert is in effect for Delhi, Haryana, Punjab, Rajasthan, UP, and parts of MP from May 18, 2026
- Temperatures in Delhi NCR may touch 45–46°C through May 22
- Set your AC to 24–26°C, the BEE-recommended range that saves up to 24% on electricity.
- Use a ceiling fan + AC together to stay comfortable at a higher thermostat setting.
- Monitor live updates at mausam.imd.gov.in
The India Meteorological Department (IMD) on Sunday issued a red heatwave alert for six states: Delhi, Haryana, Punjab, Rajasthan, Uttar Pradesh, and parts of Madhya Pradesh, effective from May 18, 2026. Temperatures in the National Capital Region are expected to hover between 43°C and 46°C through the week, with the IMD attributing the extreme heat to a combination of dry northwesterly winds, anti-cyclonic circulation over Rajasthan, and the worsening urban heat island effect across Delhi’s concrete sprawl.
According to the IMD bulletin, a heatwave is officially declared when plains record temperatures of 40°C or above and the reading is 4.5°C or more above normal. By that measure, Delhi is firmly in the red zone and is expected to remain there until at least May 22.
With over 200 million air conditioners running across India this summer (CEEW, 2024), how you operate yours over the next five days will determine both your comfort and your electricity bill.
Below is a data-driven overview of how to manage your air conditioning efficiently during the heatwave.
The Most Common AC Mistake During the Delhi Heatwave
Many people believe that setting the AC to 18°C will cool a room faster. In reality, this approach does not speed up cooling and leads to higher electricity consumption.
When you set the thermostat to 18°C, the compressor operates at full capacity until the room reaches that temperature. In many homes with poor insulation or direct sunlight, the AC may never reach this target, resulting in high electricity bills and less effective cooling.
The Bureau of Energy Efficiency (BEE), under the Ministry of Power, has recommended 24°C as the default thermostat setting for all air conditioners in India since 2018. At 24–26°C, an inverter AC consumes roughly 24% less electricity than at 18°C, with a negligible difference in perceived comfort — especially when paired with a ceiling fan.
How to Stay Cool During the India Heatwave 2026 While Managing Electricity Costs
1. Set Your AC to 24–26°C (Not 18°C)
Setting your AC between 24°C and 26°C, as recommended by the BEE, provides a good balance between comfort and energy efficiency. According to BEE data, each degree below 24°C increases energy use by about 6%. At night, increasing the thermostat by 1–2°C is usually sufficient, since the body needs less cooling during sleep.
2. Run Your Ceiling Fan Simultaneously
Running a ceiling fan costs about ₹0.50 to ₹0.75 per hour. When used together with an AC, the fan helps distribute cool air more evenly, so you can set the thermostat 2°C higher without sacrificing comfort. This approach can reduce AC electricity consumption by 15 to 18% compared to using the AC alone at a lower setting.
3. Seal the Room Completely
To prevent cool air from escaping, close all windows and doors. Use curtains or blackout blinds on south- and west-facing windows, since glass allows solar radiation to enter and increases the room temperature. Rooms exposed to direct afternoon sunlight can be 5 to 8°C warmer than those with blinds drawn, which forces the AC to work harder.
4. Avoid Heat-Generating Appliances Between 12 PM and 5 PM
Appliances like ovens, stovetops, dryers, and desktop computers generate heat when in use. Limiting their use between noon and 5 PM during the heatwave reduces the thermal load on your AC and helps maintain a stable room temperature with less energy.
5. Clean Your AC Filters Every Two Weeks During Summer
Dust buildup in AC filters is a common cause of reduced performance in Indian homes. When filters are dirty, the unit uses more power to deliver less airflow. Cleaning indoor filters every 10 to 14 days during a heatwave helps maintain efficiency.
6. Use Dry Mode in Humid Conditions
During periods of high humidity, which are common before the monsoon in Delhi, use the dry mode on your AC. This setting removes moisture from the air more efficiently than standard cooling mode. Lower humidity makes the room feel cooler at the same temperature, so you are less likely to lower the thermostat unnecessarily.
7. Don’t Switch Off Your Inverter AC Frequently
Inverter ACs are designed to maintain efficiency by adjusting compressor speed instead of turning on and off. If you plan to leave the room for less than 30 to 45 minutes, it is more efficient to keep the unit running at a stable temperature. Restarting the AC after a short break uses more energy due to the initial power surge.
8. Maintain the Outdoor Condenser Unit
The outdoor unit releases heat from inside your room. If it is blocked by dust, debris, or exposed to direct afternoon sunlight without shade, its efficiency decreases. Keep the area around the unit clear by at least 30 to 45 cm on all sides. Adding a simple shade canopy, while ensuring airflow is not restricted, can help improve performance during the hottest part of the day.
Delhi Heatwave 2026: When Will It End?
According to the IMD’s extended forecast, the current heatwave conditions over Northwest India are expected to persist until May 22–23, when a weak Western Disturbance may bring partial cloud cover to parts of Delhi and Punjab, offering some relief. However, temperatures are unlikely to drop below 40°C before the last week of May.
The IMD’s official heatwave status can be tracked in real-time at mausam.imd.gov.in and via the Damini and Meghdoot apps.
Frequently Asked Questions: Delhi Heatwave May 2026
1. Which states are under IMD heatwave alert from May 18, 2026?
The IMD has issued a heatwave alert covering Delhi, Haryana, Punjab, Rajasthan, Uttar Pradesh, and parts of Madhya Pradesh, effective from May 18, 2026. Parts of the Delhi NCR may record temperatures above 45°C during peak afternoon hours.
2. What temperature qualifies as a heatwave in India according to IMD?
The IMD defines a heatwave as a condition in which the maximum temperature in plains regions reaches 40°C or higher and is at least 4.5°C above normal. For coastal stations, the threshold is 37°C or above. A severe heatwave is declared when the departure from normal exceeds 6.4°C.
3. What is the best AC temperature during a heatwave in India?
The Bureau of Energy Efficiency (BEE) recommends setting your AC to 24°C. This setting reduces electricity consumption by approximately 24% compared to 18°C, with no meaningful loss in comfort when a ceiling fan is used. Drop to 26°C at night.
4. Does setting AC to 18°C cool the room faster than 24°C?
No. Air conditioners cool rooms at roughly the same rate regardless of thermostat setting — the compressor either runs or it does not. Setting a lower temperature only means the compressor runs for longer, increasing power consumption without speeding up initial cooling.
5. How does the urban heat island effect worsen heatwaves in Delhi?
The urban heat island effect occurs when dense concentrations of concrete, asphalt, and buildings absorb solar radiation during the day and re-radiate it as heat at night, preventing temperatures from dropping meaningfully after sunset. Delhi’s daytime high may be 45°C while the surrounding rural areas record 41°C. The effect also means Delhi nights rarely drop below 30–32°C during a heatwave, limiting the body’s overnight recovery.
6. Should I use cool mode or dry mode during the heatwave?
Use cool mode when the room is hot but not particularly humid. Use dry mode in pre-monsoon conditions when humidity is elevated — it removes moisture from the air more efficiently, making the ambient temperature feel significantly lower without running the compressor as hard.
7. How often should I clean my AC filter during the Delhi heatwave?
During peak summer, clean your indoor unit’s air filter every 10–14 days. A clogged filter can reduce airflow efficiency by 15–25%, forcing the compressor to work harder, increasing your electricity bill, and delivering less cooling.
8. Is it more efficient to leave an inverter AC on or turn it off when leaving the room?
For absences under 30–45 minutes, it is more efficient to leave an inverter AC running at a stable temperature (such as 26°C) than to switch it off. Inverter compressors maintain efficiency at low modulation. Frequent restarts, especially in a hot room, consume disproportionately more energy during the re-cooling cycle.
9. Where can I check official IMD heatwave alerts in real time?
Monitor heatwave status on the IMD’s official website (mausam.imd.gov.in), the IMD Weather app, or the Sachet early warning platform. For lightning-related hazards that sometimes accompany dust storms during heatwaves, use the Damini app.
10. What are the health risks of the Delhi heatwave 2026?
Prolonged exposure to temperatures above 40°C, especially with high humidity, can cause heat exhaustion and heat stroke. The National Disaster Management Authority (NDMA) advises avoiding outdoor activity between 11 AM and 4 PM, staying hydrated with water and ORS, wearing light cotton clothing, and never leaving children or pets in parked vehicles. If someone shows symptoms of heat stroke, confusion, loss of consciousness, or cessation of sweating, call 112 immediately and move them to a cool environment.
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