DOVER — Extreme heat like New Hampshire residents saw over the weekend of July 20 and 21 will become more common with climate change, according to a recently released report and peer-reviewed study.

The analysis by the Union of Concerned Scientists says they predict extreme heat so frequently in the near future that it is possible it will affect daily life for the average U.S. resident more than any other facet of climate change, including rising sea levels.

In New Hampshire, the number of days per year with a heat index above 100 degrees Fahrenheit will increase to six days a year by 2050 and 19 days a year by 2100, it is predicted.

At a heat index of 100 degrees, National Weather Service advisories state that heat stress or illness are possible, especially for elderly adults and small children.

Dover and Nashua are cities cited in the analysis as experiencing the highest frequency of such days. In Dover, it hit 95 degrees on July 20, according to Mayor Karen Weston. Nashua saw a high temperature of 95 degrees, according to the National Weather Service.

Weston said the city currently uses the McConnell Center for a cooling station. Residents are also invited into the public library and the lobby of the police station to get out of the heat on hot summer days.

Weston said new and remodeled buildings, such as Dover High School and Garrison Elementary School, have energy-efficient ways of keeping students cool in the spring and fall, and keeping them warm in the winter.

“Energy efficiency is paramount,” Weston said of the city’s efforts.

Justin Kates, director of emergency management in Nashua, said the city has cooling centers and offered free bus rides to air-conditioned environments including the YMCA, library, senior center or Pheasant Lane Mall on July 20 and 21.

Kates said the city has already noticed an increase in extreme heat as local officials plan for weather events that could negatively impact the health of residents.“People in New England don’t expect extreme heat events, but every summer it seems like we have more and more of these events,” Kates said.Officials in Nashua are also promoting energy efficiency in public and private buildings. Kates said new construction can use “passive sustainability,” which incorporates new building methods which trap cool air inside a building during the summer and hot air inside a building during winter.

Kates said New York City is already working to ensure new buildings have passive sustainability features.

In the Union of Concerned Scientists analysis, researchers say temperatures around the world have been increasing for decades because of heat-trapping emissions from the burning of fossil fuels.

In addition to reducing emissions, the analysis says federal and state governments must take protective measures based upon public health guidance to ensure people are safe during periods of extreme heat. That means creating a public alert system, investing in heat-smart infrastructure and investing in climate-smart power systems.