Extreme heat is in the forecast for New Hampshire. Here's how to stay safe.

This year’s first bout of extreme heat is on the horizon for New Hampshire.

The National Weather Service has issued a heat advisory for much of the state from noon to 8 p.m. Tuesday. During that time, the heat index is expected to reach the mid-90s to 100 degrees.

There’s an excessive heat watch for Wednesday and Thursday, when it’s possible the heat index will reach 105 degrees. Click here for more details from the National Weather Service.

Lee esta historia en español aquí.

Climate change is making New Hampshire hotter, and scientists expect more days of extreme heat as the burning of fossil fuels continues warming up the atmosphere.

Extreme heat can be dangerous

Across the country, the Centers for Disease Control and Prevention says more than 600 people die annually from extreme heat. In New Hampshire, a 2021 report from the Granite State News Collaborative found that more than 1,400 residents went to the ER for heat-related illness between 2012 and 2019.

Heat can have harmful effects on anyone, but some people are at even greater risk. According to the CDC, that includes older adults, young children, people with chronic medical conditions, low-income populations, athletes and people who work outdoors. Heat can also be especially dangerous to pregnant people.

Dizziness, nausea, hot skin and a rapid pulse are some of the signs of heat stroke. Heavy sweating, fainting, dizziness and headaches are some symptoms of heat exhaustion.

To stay safe during a heat wave, emergency preparedness officials advise avoiding the outdoors and sun exposure as much as possible, limiting outdoor work and sun exposure during the hottest parts of the day, and wearing loose-fitting and lightweight clothing. If you must stay inside and don’t have access to air conditioning, they also recommend staying on lower floors because heat rises.

Officials also suggest covering windows that get morning or afternoon sun with drapes, shades or awnings.

By Degrees: It's hot today. Here's how to stay cool and use less energy.

If you do need to be active in the heat – if you work outdoors, for example – drink plenty of fluids and pay close attention to how you’re feeling, said Dr. Trevor Eide, the medical director for the emergency department at Portsmouth Regional Hospital.

“Any headaches, fatigue, dry mouth, thirst suggest people should stop at that point [and go inside to cool off] – as opposed to continuing to progress until symptoms become worse,” he said.

If you notice more serious symptoms – including altered mental status, confusion, slurred speech or continuing to sweat heavily despite moving to a cooler location – it’s a good idea to seek medical attention, Eide said. Those could be signs of heat stroke, a more serious illness than heat exhaustion.

“That all suggests that the body is no longer able to compensate for the increase in heat,” he said.

Eide said older adults are especially vulnerable to heat-related illness and should have air conditioning in at least part of their home – ideally the bedroom, so the body has time to cool off overnight.

State security and emergency management officials also urge people to avoid leaving children or pets unattended in closed vehicles, even with the windows down.

If you don’t have access to air conditioning or if your home loses power, you might be able to go to a local cooling center or find an air-conditioned public space, like a library. You can call your local city or town hall for more information.

More resources:

Cooling centers across the state

Heat risk by county and actions to take to stay safe

Extreme heat safety tips from ReadyNH.gov

Tips for Preventing Heat-Related Illness from the CDC

Heat waves can also place stress on the electricity grid. Here’s some advice on how to reduce energy usage on hotter days.

A version of this story was originally published in 2022. It was updated on June 17, 2024.