NYC weather forecast for the longest day of the year, first day of summer
NEW YORK - After weeks of gray skies and nonstop rain, the Tri-State Area is finally about to get a long-awaited summer glow, but it comes a serious heat check.
The summer solstice is Friday, bringing the longest day of the year and marking the official start of summer.
A heat dome will push temperatures in New York City into the upper 90s, accompanied by dangerous levels of humidity. Heat advisories are expected, and vulnerable groups are urged to stay cool and hydrated.
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When is the first day of summer 2025?
JERSEY CITY, NJ - JUNE 19: The sun rises behind the skyline of midtown Manhattan and the Empire State Building in New York City, a day ahead of the summer solstice and an expected heatwave on June 19, 2025, as seen from Jersey City, New Jersey. (Phot
Summer officially begins on Friday, June 20, with the summer solstice marking the astronomical start of the season in the Northern Hemisphere.
The solstice occurs at 10:42 p.m. Eastern, according to the National Weather Service, when the Earth’s North Pole tilts closest to the sun.
It brings the longest day of the year with the most sunlight.
What is the summer solstice?
On the solstice, the sun reaches its highest point in the sky, delivering the most direct sunlight of the year.
This increase in solar energy signals the start of astronomical summer, bringing longer days and warmer temperatures to the region.
How hot will it get in New York City?
WPC Day 3-7 Heat Index Forecasts (NOAA)
Starting Sunday, a heat dome, a high-pressure system trapping hot air, will push temperatures well above average across New York, New Jersey, and Connecticut.
In New York City, highs could climb into the upper 90s, with heat indices making it feel like 100 degrees or more, according to NOAA.
The National Weather Service is expected to issue heat advisories as humidity rises, increasing the risk of heat-related illnesses across the tri-state area.
What is a heat dome?
Ken Kunkel, a research professor of atmospheric sciences at North Carolina State University, says it helps to think of a heat dome as what’s happening in the atmosphere, while a heat wave is the impact felt on the ground.
A heat dome forms when a high-pressure system builds in the upper atmosphere, causing the air below it to sink and compress. This process raises temperatures near the surface and traps heat close to the ground.
As the hot air expands, it creates a bulging dome that lingers for days, driving temperatures 10 to 20 degrees above normal and leading to prolonged periods of extreme heat, according to NOAA.
New York City, northern New Jersey, and southwestern Connecticut are expected to bear the brunt of this upcoming heat wave. Nearby areas like Long Island, Westchester, and the Hudson Valley will also see intense, sweltering conditions.
Who is most at risk during this heat wave?
Health officials warn that seniors, young children, outdoor workers, and those without air conditioning are especially vulnerable to heat exhaustion and heat stroke. Local authorities typically open cooling centers during extreme heat to provide relief.
When will the heat wave ease?
The intense heat is expected to last through midweek.
Relief should come by the end of June or early July when the heat dome shifts eastward, allowing for cooler air, increased cloud cover, and some rain to return to the Tri-State area.
For now, residents of New York City and its surrounding communities should prepare for a hot start to summer, stay hydrated, and check on neighbors who may be at risk.
Heat wave forecast for NYC
The prime time for a potential heat wave next week will be from Sunday through Thursday. While relatively few locations may actually hit the 100-degree mark, the combination of high temperatures and elevated humidity levels will make it feel significantly hotter.
- Sunday: Partly sunny, with a high near 86.
- Monday: Sunny, with a high near 88.
- Tuesday: Sunny, with a high near 90.
- Wednesday: Sunny, with a high near 88.
New York City has only reached the 100-degree threshold three times during the month of June. The NWS is expected to issue a range of heat-related alerts in the coming days, which may include heat advisories, extreme heat watches and extreme heat warnings, depending on the expected severity and duration of local conditions.