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As people grow weary of staying inside, more people are venturing out and growing lax on social distancing efforts meant to stop the spread of coronavirus, according to data from the University of Maryland.

The university has developed a tool using anonymous cellphone data to track social distancing compliance, and last week, for the first time, researchers saw a decline in the social distancing effort across the country by 3 percent, said professor Lei Zhang, who is leading the project.

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"What we see right now is that individual Americans — many of them are deciding on their own that they’re going to reopen themselves to go out more," Zhang said. "It’s just a major shift as the nation fights the pandemic."

In Chicago, Mayor Lori Lightfoot, who has been unwavering and stern in her instructions for people to stay home, said in a tweet that a viral video showing a crammed house party showed behavior that was "reckless and utterly unacceptable.”

Zhang said in an interview with the "TODAY" show that people are experiencing "quarantine fatigue" because they've spent weeks cooped up inside, some individual states are loosening social distancing rules and the weather is improving.

In Southern California, people packed beaches over the weekend as the temperatures soared into the 90s. Gov. Gavin Newsom on Friday had anticipated the pull of the warm weather and urged people to stay in anyway.

It’s going to be nice outside this weekend. You might be feeling cooped up. Ready for life to go back to “normal.”



But can’t stress this enough:



CA can only keep flattening the curve if we stay home and practice physical distancing.



You have the power to literally save lives. — Gavin Newsom (@GavinNewsom) April 24, 2020

On the other side of the country, on Long Island, people also packed the shores on a sunny spring Saturday. Gov. Andrew Cuomo has also anticipated and tried to discourage a decrease in caution during warmer weather.

New York, the hardest-hit state, is doing better than other states, but still saw social distancing efforts slip last week along with 43 other states, according to the University of Maryland.

Southern states like Louisiana, North Carolina, South Carolina, Tennessee and Georgia, where Gov. Brian Kemp allowed some nonessential businesses to open last week, top the list for the biggest drops in social distancing efforts last week, with Louisiana and North Carolina seeing an 9 percent increase of out-of-the-home activity.