National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce

Dangerous Heat in the Central and Eastern U.S.; Critical Fire Weather in the Great Basin and Southwest

Dangerous, record-breaking heat will intensify across most of the central and eastern U.S this week. Heat indices will likely exceed 100 degrees. Heat is likely to continue across the eastern U.S. through the Independence Day holiday weekend. Critical fire weather conditions will continue Tuesday across portions of the Four Corners and Great Basin, as dry conditions and gusty winds persist. Read More >

Hazardous Weather Conditions

Current conditions at

Morristown Airport (KMMU)

Lat: 40.8°NLon: 74.42°WElev: 187ft.

Partly Cloudy

75°F

24°C

Humidity 74%
Wind Speed Calm
Barometer 30.12 in
Dewpoint 66°F (19°C)
Visibility 10.00 mi
Last update 29 Jun 9:45 pm EDT
Extended Forecast for

Mountainside NJ

Extreme Heat Watch July 1, 12:00pm until July 4, 09:00pm
Click here for hazard details and duration
Extreme Heat Watch

  • Tonight

    Tonight: Mostly clear, with a low around 66. Light southwest wind.

    Low: 66 °F

    Mostly Clear

  • Tuesday

    Tuesday: Mostly sunny, with a high near 91. Southwest wind 5 to 10 mph, with gusts as high as 21 mph.

    High: 91 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: A 20 percent chance of showers and thunderstorms before 2am. Partly cloudy, with a low around 71. Southwest wind 7 to 14 mph.

    Low: 71 °F

    Slight Chance
    T-storms

  • Wednesday

    Wednesday: Mostly sunny, with a high near 97. Heat index values as high as 105. West wind 8 to 11 mph, with gusts as high as 21 mph.

    High: 97 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 77. Southwest wind around 7 mph.

    Low: 77 °F

    Mostly Clear

  • Thursday

    Thursday: Sunny and hot, with a high near 102.

    High: 102 °F

    Hot

  • Thursday Night

    Thursday Night: Clear, with a low around 79.

    Low: 79 °F

    Clear

  • Friday

    Friday: Sunny and hot, with a high near 101.

    High: 101 °F

    Hot

  • Friday Night

    Friday Night: A chance of showers and thunderstorms between 8pm and 2am. Partly cloudy, with a low around 76. Chance of precipitation is 30%.

    Low: 76 °F

    Chance
    T-storms

Detailed Forecast

Tonight
Mostly clear, with a low around 66. Light southwest wind.
Tuesday
Mostly sunny, with a high near 91. Southwest wind 5 to 10 mph, with gusts as high as 21 mph.
Tuesday Night
A 20 percent chance of showers and thunderstorms before 2am. Partly cloudy, with a low around 71. Southwest wind 7 to 14 mph.
Wednesday
Mostly sunny, with a high near 97. Heat index values as high as 105. West wind 8 to 11 mph, with gusts as high as 21 mph.
Wednesday Night
Mostly clear, with a low around 77. Southwest wind around 7 mph.
Thursday
Sunny and hot, with a high near 102.
Thursday Night
Clear, with a low around 79.
Friday
Sunny and hot, with a high near 101.
Friday Night
A chance of showers and thunderstorms between 8pm and 2am. Partly cloudy, with a low around 76. Chance of precipitation is 30%.
Independence Day
A 50 percent chance of showers and thunderstorms after 2pm. Mostly sunny and hot, with a high near 100.
Saturday Night
A 30 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 73.
Sunday
A 30 percent chance of showers and thunderstorms. Mostly sunny, with a high near 93.
Sunday Night
A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 72.
Monday
A 50 percent chance of showers and thunderstorms. Partly sunny, with a high near 90.
Basemap Options
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Mountainside NJ
 40.69°N 74.37°W (Elev. 417 ft)
Last Update:
3:53 pm EDT Jun 29, 2026
Forecast Valid:
10pm EDT Jun 29, 2026-6pm EDT Jul 6, 2026
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

Link to Local Radar Data Link to Satellite Data

Hourly Weather Forecast

National Digital Forecast Database

National Digital Forecast Database Maximum Temperature Forecast

High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation