Virginians might need to brace for a long, hot summer

Don't get used to the recent sweater weather. Virginia will likely face a hotter-than-usual summer , according to new forecasts and scientific research.

Why it matters: Extreme heat is a major public health threat that puts vulnerable populations at risk and can further strain the power grid during prolonged heat waves.

The big picture: Heat waves are becoming more common and intense due to human-caused climate change. Everywhere in the mainland U.S. — except for North Dakota — is projected to be hotter than average from June to August, with varying odds.

• Virginia, for example, has a 40% to 50% chance. The odds increase to 60% to 70% further north.
• Winters are also getting warmer ; allergy season is longer , and the risk of flooding due to heavy rain is higher.

Zoom in: Virginia is already having one of its warmest recorded starts to a year, reports the Times-Dispatch's Sean Sublette .

• And Richmond has been averaging 48 days at or above 90°F this century compared to an average of 39 days in the 1900s.

Between the lines: Some Richmond neighborhoods will face even hotter temperatures because of the heat island effect , where fewer trees to cover pavements means the concrete absorbs and traps heat.

• This is often concentrated in lower-income neighborhoods that were further segregated by discriminatory housing laws in the 1930s known as redlining.
• Some of the hottest areas like Gilpin Court, a public housing community that was once redlined, can see temperatures up to 15°F hotter than wealthier parts of the city.

By the numbers: Richmond had 120 heat-related illness visits from May to September last year — the third-highest number in the state and the city's highest number recorded since 2015, according to Virginia Department of Health data .

What's next: The National Weather Service and the CDC are rolling out an experimental heat forecast tool that can give health guidance up to seven days in advance.