The people of Pune are having a dreadful summer. The thermometer says it’s 38°C, but the humidity makes it feel like it’s 45°C or higher. The wet bulb temperature metric depicts how air with a lot of moisture changes controllable heat into a serious health risk. City planners and residents need to pay attention to this right away.
Learning About Wet Bulb Temperature
The wet bulb temperature shows how temperature and humidity affect the body as a whole. Wet bulb readings are different from dry bulb readings because they show how well sweat drains from the skin, which is how we cool off. When the humidity goes up, evaporation slows down. This keeps heat in the air and makes it seem heavy. This is what people in Pune are saying right now, during the first heat wave of March 2026.
The weather in Pune lately has showed that the air temperature is regularly between 37 and 39 degrees Celsius and the relative humidity is often around 70%. The heat index, that deceptive “feels like” number, creeps into the mid-40s. It’s more than just unpleasant. Prolonged exposure to these conditions places significant strain on the heart and lungs. It heightens the chances of dehydration and can lead to heatstroke, a particular danger for the elderly and those whose jobs keep them outdoors.
Experts say that wet bulb readings over 28°C are bad for you. At night, when winds should help, Pune has been near to 30°C wet bulb thresholds.
You may easily comprehend the science: you wrap a wet cloth over a wet bulb thermometer and spin it in the air. The value is lower than in dry air because evaporation cools the air. When the humidity is high, less water evaporates, which makes the wet bulb’s temperature grow closer to that of the dry bulb. This shows that the body can’t cool itself down enough. Pune sits under the rain shadow of the Western Ghats, but it gets moisture from the Arabian Sea. This is the ideal storm of sticky heat for the city.
The Science of “Felt” Temperature
Humidity keeps sweat from evaporating when the air is already wet. This makes the body moist instead of cool. Think about how bad it would be to wear a coat that was always wet in a sauna. That’s how your body really works. When the humidity is 40%, sweat dries fast, which cools the skin. At 80% humidity, sweat doesn’t move much, which raises the body’s core temperature.
This is worse because of Pune’s microclimate. The city has grown quickly, and currently more than 7 million people live there. Concrete jungles that trap heat have taken the place of natural regions. When the winds transport moisture from the Bay of Bengal and there are only a few pre-monsoon showers, the humidity rises without any rain to help it. The local weather stations in Shivajinagar and Lohegaon reveal that the humidity at night nearly never drops below 60%. This implies that the normal cooling that happens at night to reset the heat stress of the day doesn’t happen.
The heat index tells you how hot it feels by combining the quantity of moisture in the air with the temperature of the air. For example, when the temperature is 38°C and the humidity is 40%, the heat index rises to 42°C, which means you should be careful. When the humidity is 60%, it can get as high as 46°C, so be very careful. It is harmful when the humidity climbs beyond 80% and the temperature rises to 52°C. The temperature rises to 50°C at 39°C with 70% humidity, which is quite dangerous. These examples show why Pune’s weather right now, which is 38°C on average and 65–75% humidity, feels like 45–48°C. This puts it in the red zone, where you can acquire heat exhaustion in less than an hour of being outside. Doctors say that in March, there were 30% more hospital visits for heat-related problems than in March of last year. It shows how readings on a thermometer are different from real life.
The One-of-a-Kind Heat and Humidity Trap in Pune
People have thought of Pune as the coolest hill station in Maharashtra for a long time, but that’s changing. Development along the Mula-Mutha rivers has blocked natural air movement, and climate change makes things even less predictable. The India Meteorological Department (IMD) warned that from March to May 2026, temperatures would be higher than normal, and central Maharashtra would probably see heat waves. Not many people noticed the big rise in humidity coming because the weather is so unpredictable.
Things in the vicinity make the problem worse. The factories in Chakan and Pimpri-Chinchwad release gases that trap heat. Pune has more than 4 million cars, so traffic jams are typical. These contribute exhaust fumes that make the air quality and heat worse. The humidity is rising early because of climate change, and the winds from the east are bringing wet weather as El Niño changes to La Niña. People who live in places like Koregaon Park and Baner say that mornings seem like steam rooms since the dew points are always above 24°C, which indicates the bulb is wet.
People who exercise at Taljai Hills Park and shop at the Laxmi Road markets have related stories that make it quite clear: “The air clings to your skin,” says one autorickshaw driver. The average wet bulb temperature in Pune has gone up 1.5°C in the last ten years. This is in line with what is happening around the world, but it has happened faster because of local deforestation.
Groups and people that are at risk of health problems
High wet bulb conditions are bad for more than just being uncomfortable; they can even kill you. When the wet bulb temperature reaches 35°C, even healthy adults can’t stay there for long because their bodies get too hot. Pune isn’t there yet, but the events last week that were 31–32°C rang bells.
Weak organizations are the ones that are most affected:
People who work outside in construction or delivery have to deal with the hottest part of the day for 8 to 10 hours, which causes them sweat more than 2 liters an hour.
Older people and kids are more likely to get cramps and feel tired since they can’t control their body temperature as well. Schools are canceling classes in the middle of the day.
People with diabetes or heart problems who also have other health issues know that their symptoms get worse. There are now twice as many persons with hyperthermia in hospitals.
Some of the symptoms that get worse quickly are dizziness, nausea, a fast heartbeat, confusion, and organ failure. To stay healthy, drink 4 to 5 liters of water every day, keep your electrolytes in balance, and take rests in the shade. But people still don’t know enough. Many of them still believe dry bulb forecasts and don’t pay attention to humidity warnings.
How to Keep People Safe in Pune
People can fight back by doing things that are good. Plan your workouts for early in the morning or late at night, and wear clothes made of light, breathable materials like cotton. Fans can help with evaporation when the humidity is 50% or higher. Not simply water, but also oral rehydration solutions, should be drunk ahead of time to replace salts.
The Pune Municipal Corporation (PMC) is responding to the heat wave. They’re setting up cooling centers in places like shopping malls and libraries.
Misting stations are being installed at bus stops, too. Furthermore, urban forestry projects are underway, with a goal of planting a million trees by 2027.
However, the implementation isn’t always smooth. Illegal hoardings block out shade, and footpath encroachments disrupt airflow.
Proponents of “green infrastructure” suggest a range of solutions. Examples of these methods include permeable pavements, which allow rainwater to soak into the ground, rooftop gardens that help control building temperatures, and stricter building codes that require reflective roofing materials.
Smart technology, such as wet bulb monitoring in public areas, could provide real-time alerts via apps, giving people more agency.
A Snapshot of Maharashtra’s Weather Woes
The difficulties faced in Pune mirror broader issues across the state of Maharashtra.
The mercury is climbing in both Nashik and Ahmednagar, cities that sit side by side. Meanwhile, the humidity along Mumbai’s coastline can soar to 90%, resulting in a dangerously high wet bulb temperature.
Agriculture is hurting all over the state. During hot, humid weather, mango and sugarcane yields drop by 15–20%, which affects food supply chains in Pune.
Predictions about the weather say things will get worse. By 2030, Pune might have 20 more days of heat waves every year, and wet bulb mishaps could happen twice as often. This is like what happens in cities all around the world, where urban heat islands make the temperature rise by 2 to 3 degrees Celsius. The National Action Plan on Climate Change in India is all about adapting, but it can’t be put into action since there isn’t enough money.
Pune is distinct because its normal March temperatures of 38°C and 70% humidity make it feel like 46°C, which is worse than Delhi’s 40°C or Bengaluru’s 41°C. Mumbai’s 48°C is similar, but it has more moisture in the air.
What the experts and the government said
The relief minister of Maharashtra said that ₹100 crore would be spent on lessening the effects of heat. This includes 500 new ambulances for people who have heatstroke and commercials in Marathi and Hindi to raise awareness. The IMD has improved its forecasts by adding heat index maps that anyone may see through the Mausam app.
The dean of IMD in Pune and other meteorologists underline how crucial education is by saying, “Wet bulb isn’t abstract—it’s survival math.” We can make AI-based predictions that take changes in humidity into consideration with the help of IIT Bombay. Sankalp and other non-governmental organizations (NGOs) supply free cooling kits to slums, where the tin roofs make the inside of dwellings hotter than 50°C.
The “Wet Bulb” Effect: Why Pune’s Humidity Makes It Feel Like 45°C
