Fourth of July temps could break records on Long Island, but holiday could be dampened by thunderstorms

Scores of friends and families will congregate outdoors for barbecues and aerial pyrotechnics on Saturday for what forecasters say could tie with — or even surpass — Long Island’s hottest Independence Day on record.

The smoldering heat and sticky humidity of Long Island’s first heat wave of the summer will stick around on Saturday. The high temperature recorded in Islip on Friday was 97 degrees, according to the National Weather Service, no sweat compared with the 104 degrees of July 3, 1966.

The high is forecast to soar to 97 in Islip once again on the Fourth, but just like every day since the weather service issued an extreme heat warning on Wednesday, it will feel much worse — around 105 — due to the humidity, meteorologist Bryan Ramsey told Newsday.

The hottest Independence Days on record — when temps hit 97 degrees in Islip — were measured in 1966 and 2010. The weather service’s climatological records for Islip date back to 1963.

“Right now, we’re forecasting that record to tie, so there is a chance that that record could break,” Ramsey said. “We’re forecasting 97 or 98 degrees.” 

While the heat will be just as high, air quality will improve on Saturday. Due to high ozone levels on Friday, the New York State Department of Environmental Conservation deemed the air unsafe for seniors, children, pregnant women and those with respiratory conditions. Saturday’s levels will be considered acceptable, but still pose a moderate risk to sensitive groups, especially when coupled with temporary localized spikes in pollution caused by fireworks.

The morning and afternoon hours will be the ideal time for any outdoor revelry on Saturday, according to Ramsey, although the weather service notes that increasing clouds after 2 p.m. could be accompanied by scattered showers and thunderstorms. 

Come evening time, especially “just after sunset, it does look like we could see showers and storms around that time,” he said.

“Some could be on the stronger side, with heavier downpours and gusty winds,” Ramsey added. “The biggest concern for us is lightning with these storms as well. A lot of people are going to be outdoors, and lightning causes a lot of fatalities every year.” 

Thunderstorms and scattered showers could return on Sunday, but temperatures will finally vacate the 90s. Rain is most likely in the morning and the evening, Ramsey said, with a possibly salvageable “lull” in the afternoon, when the high will only reach the mid- to upper 80s.