This week’s dangerous heat is no joke, NJ’s worst heat wave in four years

The Bottom Line

As we prepare to turn the calendar page from June to July, and get ready for the big Fourth of July holiday weekend coming up, the big weather headline is big heat building in. A heat wave began on Monday and will continue for at least a week. This is not a friendly weather forecast, as we face near-record and downright dangerous conditions in the coming days. Highs will reach about 90 degrees on Tuesday, into the 90s on Wednesday, near 100 on Thursday, and then into the 100s on Friday, likely the hottest day of the week. High humidity could push the heat index close to 110 degrees at times. A few bouts of spot thunderstorms are possible in this soupy atmosphere too, a possibility we will especially have to watch on the Fourth of July holiday itself on Saturday.

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Weather Hazards

Dangerous heat is our top weather hazard by far. An Extreme Heat Warning is already posted for almost all of New Jersey from noon Wednesday right through the Fourth of July on Saturday. We are talking about near-record temperatures, potentially in the triple digits, with the heat index or "feels like" temperature even higher. This is downright dangerous heat — you have to take care of yourself in such conditions, staying extra hydrated, dressing for the weather, and taking frequent cooldown breaks.

There is also a chance for a few thunderstorms in this soupy atmosphere. A pop-up storm is possible Tuesday evening, mainly across the northern half of the state. A few storms are possible late Wednesday too. Any storm that forms could produce heavy rain and gusty wind, although widespread severe weather is not the primary concern.

Climatological Context

June 30 is the 181st day of 2026.

Normal high temperatures range from 85 to 86 degrees, while normal low temperatures range from 65 to 68 degrees.

June is, on average, New Jersey's third warmest and third wettest month of the year.

July starts Wednesday. And it is, on average, the granddaddy of New Jersey's climatological calendar — the hottest and the wettest month of the year.

Tuesday

I am holding my horses on the "extreme" lingo for now, as Tuesday stays reasonable and out of the danger zone.

New Jersey closes out June with one more very warm day, by the numbers fairly similar to Monday. Temperatures Tuesday morning are mainly in the 60s around the state, with just a hint of stickiness in the air. (Say goodbye to any semblance of comfortable air, because temperatures and humidity will be on the rise through the rest of the week.)

Tuesday will feature mostly to partly sunny skies and high temperatures around 90 degrees. The Jersey Shore should be a bit cooler, as long as a sea breeze kicks in through the afternoon.

There is a chance for one or two pop-up thunderstorms Tuesday evening as temperatures start to cool. The chance is limited and very much few and far between, but a storm cell could bubble up, especially across the northern half of New Jersey. The rest of Tuesday night will be clear and muggy, as low temperatures only dip into the lower 70s.

Wednesday

Wednesday turns hotter and more humid, with high temperatures reaching into the lower to mid 90s. The heat index (the "feels like" or "apparent" temperature) will flirt with 100 — this is when the heat starts to cross from uncomfortable into concerning.

An Extreme Heat Warning kicks in at noon Wednesday for most of New Jersey (all but coastal and southern parts of the state), and continues through sunset Saturday. That alone should tell you this is not ordinary summertime heat. The combination of higher humidity and temperatures well into the 90s will push heat index values higher and higher through the rest of the week.

A few strong thunderstorms are possible late Wednesday. This storm activity will likely be more widespread than Tuesday. Once again, not everyone will see rain. But any storm that develops in this soupy air could pack heavy rain and gusty wind.

Thursday

Thursday brings dangerous heat and humidity under blazing sunshine.

High temperatures will climb into the upper 90s to around 100 degrees.

This is the kind of heat that requires care and planning. Limit strenuous outdoor activity, take frequent breaks, and drink plenty of water.

Beaches and barrier islands should end up cooler than inland New Jersey. But the degree of relief will vary from beach to beach and day to day. Even at the Shore, this will be a hot stretch.

Friday & Beyond

Friday is the 3rd of July, a holiday and getaway day for many New Jerseyans. And it looks like the hottest day of the week.

Near-record heat will continue under mostly sunny skies. High temperatures will surge to about 100 and 105 degrees. The heat index could exceed 110 degrees at times.

For perspective, New Jersey's all-time record high temperature is 110 degrees, set back in 1936. We are not forecasting that number outright, but the fact that some guidance is even close to that number is enough to take this heat wave very seriously.

The Fourth of July on Saturday stays brutally hot and humid, with highs in the 90s at least. I am also concerned that a couple rounds of thunderstorms are possible for the holiday both early and late. That chance will need to be watched carefully given holiday travel plans, barbecues, beach trips, and fireworks.

When will the heat break? The European model shows a storm system driving in rain and cooler air early next week. The GFS model keeps the heat ridge firmly in place until the midpoint of July. So take your pick at this point — it could be a steamy month.

Dan Zarrow is Chief Meteorologist for Townsquare Media New Jersey. Follow him on Facebook for the latest forecast and realtime weather updates.