D.C. region braces for record-hot Fourth and Metro heat

D.C. region – Forecasters warn the D.C. area could see its hottest July Fourth on record, with multiple days of 100-degree highs, extreme heat warnings, and storm risks that could disrupt plans. Metro is also adjusting operations—adding reflective white paint to heat-expose

Saturday’s forecast called for 101 degrees, and officials are treating it like a warning shot for the holiday weekend.

The 7News First Alert Chief Meteorologist Veronica Johnson said the record for the Fourth at 100 degrees dates to 1919. This year’s forecast doesn’t just suggest another hot holiday—it points to a stretch of 100-degree days that officials say could be dangerous.

Starting Thursday and continuing through Saturday, the D.C. region is expected to experience its hottest stretch of weather so far this year. 7News First Alert Meteorologist Eileen Whelan said highs will reach around 100 degrees. with humidity pushing “feels like” temperatures to about 110 to 112 during both afternoons.

The National Weather Service has extreme heat warnings in effect for both Thursday and Friday.

Thursday is expected to be sunny and scorching, with little chance for cooling thunderstorms. Whelan said the region will see only slight relief after sunset—lows slightly below 80 degrees. with feels-like temperatures staying around 90 until after midnight. Portions of the D.C. region have opened cooling centers in preparation for the heat wave.

Friday could bring changes, though not enough to cool things down for long. Whelan said pop-up showers and storms are possible, and more widely scattered showers and storms are expected for the Fourth of July.

She also described the storm threat in terms of severity for holiday plans. Whelan said the Storm Prediction Center has placed the area in severe risk categories both tomorrow and Saturday. with a higher risk on Saturday. The concern, she said, includes damaging wind gusts, downpours, and frequent thunder and lightning.

If storms roll in earlier on July Fourth, it might not be quite as hot—but Whelan warned it would still be very humid for fireworks. With light winds, the region could also see smoke linger, creating poor air quality Saturday night.

Sunday is forecast to be slightly cooler, with highs in the 90s, along with showers and storms likely. A cold front is expected to drop highs into the 80s next week, though extreme heat and humidity are still expected to persist. Whelan said the storm chances over the next few days could be strong.

“So just take it easy,” she said.

Heat is also being monitored underground, and not just on the street. Metro has conducted “heat rides” in past years to check outdoor rail temperatures and look for warping and other heat-related issues. It has also lowered train speeds when outdoor rail temperatures top 135 degrees.

This year, Metro said Wednesday in a post on X that it is adding something new: applying reflective white paint to vulnerable segments, which lowers temps. Metro said more than 6,000 feet of track were treated with the paint.

The system’s reasoning is mechanical and immediate. Extreme heat, Metro said, can push rail temperatures above 135°F, which may cause bends in the rail due to thermal expansion. Metro has monitored rail temperatures on “heat rides” for years to detect track issues before they happen.

Metro’s chief infrastructure officer, Theresa Impastato, said, “Extreme heat presents challenges for every transit system, because our steel rails expand as temperatures increase, and the demands on our electrical and mechanical equipment increase exponentially.”

In underground stations, Impastato said chillers and fans keep temperatures about six to 10 degrees cooler than outside. She added that Metro monitors real-time conditions across the system and watches the performance of the chillers. while remaining prepared to respond quickly to any equipment issues that could affect customer comfort.

The forecast for the coming days paints a narrow window for anything that isn’t already uncomfortable.

Thursday: sunny, dangerous heat, with highs of 100–105 and a heat index of 108–112. Winds are expected from the southwest at 5–10 mph.

Thursday night: mainly clear, with lows of 77–83 and light & variable winds.

Friday: mostly sunny with dangerous heat and isolated PM storms possible. Highs are forecast at 100–106, with winds from the west at 5–10 mph.

Saturday: an extreme heat watch is expected to be issued. Highs are forecast around 100, with a thunderstorm risk and winds from the west at 5–10 mph.

For fireworks: lingering showers and storms are expected to end. with temperatures in the 90s to the 80s and winds from the west at 2–5 mph. Most fireworks displays should be able to proceed, but conditions will need to be monitored closely. Any thunderstorms developing in the afternoon or evening could linger into the early nighttime hours. especially east of the Blue Ridge. Outside storms. temperatures are expected to remain in the upper 80s to lower 90s early in the evening with very high humidity. Light winds—generally from the west around 2 to 5 mph—could also mean smoke from fireworks may linger longer than usual and reduce visibility at some displays. The forecast urged people to check radar before heading out because a thunderstorm could quickly bring dangerous lightning and strong wind gusts.

Sunday: scattered showers and storms, with highs in the 95–100 range and winds from the west at 10–15 mph. Even as the heat wave may weaken early next week, Sunday is expected to keep heat safety front and center.

WTOP’s Nick Iannelli contributed to this report.

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