Unusually hot summer forecast for Chicago

​​The Chicago area is expected to have a hotter-than-usual summer, according to new forecasts and scientific research.

Why it matters: Extreme heat is a major public health threat and plays a role in droughts and wildfires.

• Hot weather, particularly when it occurs during prolonged heat waves, also threatens the reliability of the nation's increasingly strained electric grid .

The big picture: Everywhere in the Lower 48 — except for North Dakota — is projected to be hotter than average, but with varying odds.

• Chicago, along with areas spanning from the UP all the way down to Florida, has a 40% to 50% chance of an unusually hot summer.

This comes as summers have been getting hotter over time due to human-caused climate change and sprawl.

• Chicago could also see higher temperatures based on the Urban Heat Index, which takes into account the built environment. The average UHI index per capita is highest in New York (9.5°F), San Francisco (8.8°F), and here in Chicago (8.3°F), based on data crunched by Climate Central.

The National Weather Service recently unveiled an expanded "HeatRisk" forecast map, with a color-coded scale aimed at communicating the health risks from heat exposure.

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