Watch CBS News

Philadelphia Weather: First Heat Wave Of Season Begins This Weekend

PHILADELPHIA (CBS) -- Summer in the city is getting an early start this year. We're only at the beginning of June, and summer doesn't officially start for a few more weeks, but we're getting an early dose of the dog days this weekend and likely into the start of the week too.

When we think of heat waves, we typically give them the definition of three days or more of high temperatures of 90 degrees or warmer. While there are some discrepancies about whether that is the true definition or not, it is an easy starting point when it comes to quantifying the idea of a heat wave.

For the purposes of this blog post, we will go with the standard definition of three days or more in the 90s.

So far in 2021, we have already had three days where our temperatures have the 90-degree mark in Philadelphia. We are looking to match that number or even beat it in just the next week across the Philly metro area.

It has been a little over a year since our last heat wave occurred in the city. In August 2020, we had a three-day stretch in the 90s from August 10-12, and while we had a couple more highs in the 90s throughout the rest of the month, we never hit three consecutive days after August 12.

While it is not uncommon to receive 90s in June, we typically get around five 90 degree days in the month. The idea of heat waves in June is somewhat uncommon. The last time we had a June heat wave was 2019, when all four 90 days that year happened consecutively.

The heat wave that is set to begin this weekend will likely only hit the bare minimum for the requirements, but it would make it the second time in the last three years we had an official heat wave in the month of June.

Our weekend forecast looks like this. Saturday, we will have plenty of sunshine and warm air will be pumped in the region on the back of a breezy southwest wind. Highs Saturday afternoon will jump into the low 90s for many areas, with a high of 91 in Philly.

Then on Sunday, we are likely to get even warmer. High temperatures Sunday are forecast to soar to 94 in Philly. The humidity on Sunday will be higher as well, meaning we could have heat index values that make it feel more like the upper 90s.

Then on Monday, we are once again looking at highs in the low 90s with uncomfortable humidity, leading to more heat index value in the mid to upper 90s. That makes it three days in a row and thus our first heat wave of the season in Philly.

While no heat alerts have been issued just yet, we will have to be on the lookout for alerts, like heat advisories, to possibly be issued in the urban corridor Sunday and Monday.

This is also a good time to remember to always limit your time outside and to check on the vulnerable people around you like the elderly. Also, it would be wise to limit time outdoors over the next few days and try to stay inside in the A/C as much as possible.

A good place to try and beat the heat this weekend will be at the shore. It will be in the 80s even on the sand this weekend. The water will be very inviting with the hot temperatures in place but make to swim by the lifeguards as there is a moderate risk of dangerous rip currents Saturday before the threat diminishes to low risk on Sunday.

While the 90s will likely subside after Monday it will still be hot and humid, so we will be staying hot weather aware over the course of the next week in Philly and across the whole metro area.

Stay cool and stay safe this weekend everyone.

View CBS News In
CBS News App Open
Chrome Safari Continue
Be the first to know
Get browser notifications for breaking news, live events, and exclusive reporting.