Tuesday is NJ’s hottest day of the week, Wednesday goes from steamy to stormy

The Bottom Line

Tuesday will be the hottest day of the week, as steamy temperatures once again flirt with record highs. A Heat Advisory is in effect for most of New Jersey, cautioning that the heat index could reach the upper 90s, making it especially important to dress appropriately for the heat, stay extra hydrated, and take frequent breaks in a cool spot. An Air Quality Alert has been issued too, meaning the level of air pollution will be unhealthy for sensitive groups, such as the very old, the very young, and those with heart and lunch issues. This May heat wave will end with a bang on Wednesday, one more ferociously hot day followed by a round of late-day strong thunderstorms. With clouds and showers around, Thursday and Friday will turn much cooler, with highs only in the 60s. The Memorial Day Weekend unfortunately will start even cooler, grayer, and wetter.

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Weather Hazards

A Heat Advisory has been issued for most of inland New Jersey until Tuesday 8 p.m. (For the Philadelphia metro area, the advisory extends until Wednesday 8 p.m.) With a heat index expected to climb into the upper 90s, there is an increased risk of heat-related illness. Dress appropriately for the weather, stay extra hydrated, and take frequent breaks in a cool place.

In addition, an Air Quality Alert: Code Orange is in effect once again Tuesday. Ground-level concentrations of ozone will be higher than usual, which could be unhealthy for sensitive groups like the very old, the very young, and those with heart and lung issues. If you fall into one of those categories, you should spend as much time indoors in air conditioning as possible.

If a thunderstorm does pop up Tuesday, it could become severe with gusty winds, heavy rain, and lightning being the primary concerns. Any storm activity would be isolated, and likely limited to the evening hours.

Wednesday's thunderstorms will be much more widespread, capable of producing strong winds, torrential downpours, hail, and frequent lightning. Everyone should keep a close eye on the sky Wednesday evening, as these storms could put a quick end to any outdoor activities.

Climatological Context

May 19 is the 139th day of 2026.

Normal high temperatures are still around 73 degrees across New Jersey. Normal lows range from 52 to 55 degrees.

On average, May is the 5th warmest, 5th driest, and 8th snowiest month of the year.

Tuesday

There are two changes in Tuesday's forecast, compared to Monday's weather: A shift in wind direction, and the addition of a popup thunderstorm chance. Otherwise ... ready, set, sweat once again.

Tuesday morning is starting out with temperatures around 70 degrees. Not the most stifling, suffocating, tropical morning — but definitely a warm start to another hot day.

This will be heat wave day #3 of 4. High temperatures will reach the mid 90s, with a heat index inching toward the upper 90s. Only beaches and barrier islands will find some relief from a sea breeze, less prominent than Monday, with coastal high temperatures around 80 degrees.

This is definitely a notch above "regular, everyday" heat, especially considering how early in the season it is. Please take care of yourself out there. As I often say in the summertime, air conditioning is your friend!

Expect mostly sunny skies, breezy conditions, and generally dry weather. There is a chance of an isolated thunderstorm around dinnertime Tuesday evening, fueled by this soupy atmosphere.

Tuesday night will feature a few clouds, and will be warm and sticky again. Overnight low temperatures will dip into the lower 70s.

Wednesday

With a cold front on the horizon, Wednesday is New Jersey's big transition day, starting steamy and ending stormy.

Most of Wednesday will be just like the rest of this heat wave. The day will start sunny and hot, with highs back in the lower 90s.

Scattered thunderstorms will not come into view for northwestern New Jersey until the mid afternoon at the earliest. Most likely timing for storms would actually be the evening hours.

As storms sweep through the state, they will almost certainly be strong to severe, given how "juicy" our atmosphere is. Gusty winds, torrential downpours, hail, and frequent lightning are possible — make sure you are keeping a close eye and ear on the sky.

Thursday

Thursday will be a full 30 degrees cooler than the previous days, as our heat wave comes to an end. We flip right back to our former spring pattern of dreary, unseasonably cool weather.

Owing to cooler air, clouds, and spotty rain, highs on Thursday will only reach the 60s. (Remember, normal highs for mid to late May are lower 70s.)

The best chance for wet weather will be in South Jersey. I don't think Thursday's rain will be steady or heavy, but the day could be wet at times anywhere in the state. At the same time, we should see some peeks of sun mixed with clouds.

Friday & Beyond

Friday will be similar to Thursday, perhaps trending a bit drier overall. Mostly cloudy to overcast, with the best chance of showers early and late. Highs again in the 60s. (Actually, southern and coastal New Jersey may be stuck in the 60s.)

And that brings us to the big Memorial Day Weekend. Sigh. I do not like what I see, for Saturday in particular. As our next impulse arrives, it looks like fairly steady rain will be with us throughout Saturday. Yes, we desperately need the rain — but why does it have to come to kickoff the holiday weekend?!

In addition to wet, Saturday will be cloudy and miserably cool. Forecast high temperatures are only in the lower 50s. Instead of bathing suits, you'll be donning jackets and hoodies to start the weekend.

Sunday looks better but not great. I am seeing only early and late shower chances, breaks of sun, and highs closer to 60 degrees.

The best shot at decent weather this weekend looks to be Memorial Day Monday. I'm optimistically calling for a dry daytime, with a mix of sun and clouds, and high temperatures closer to 70 degrees. Not quite beach or pool weather, but definitely an improvement.

Usually, we look for better clarity regarding the weekend forecast on Wednesday. So I suspect I will have more confident details to share about MDW soon.

In the meantime, stay cool, get ready for some storms, and think very carefully about your outdoor plans this weekend. What a wild week of weather, huh?

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