Philadelphia is kicking off a scorching Sunday, May 17, with temperatures climbing to near 90°F under mostly sunny skies — the opening act of a genuine heat wave that will stretch through most of next week.
Today’s Setup
The National Weather Service forecasts a high near 90°F inland today, with a light west wind of 5 to 10 mph. Skies stay mostly sunny with just scattered clouds. There’s a slim 10% chance of an isolated shower, but NWS forecasters note that atmospheric forcing is too weak for organized activity — the vast majority of Philadelphia stays dry. Heading down the shore? Atlantic City, Wildwood, and Cape May will run 5 to 10 degrees cooler than inland thanks to the afternoon sea breeze, with highs near 80°F along the coast.
Allergy sufferers take note: warm, dry, and breezy days like this are prime for elevated pollen counts. Keep that in mind before spending the afternoon in Fairmount Park or along the Schuylkill River Trail.
Heat Risk This Week
This is not a one-day event. The National Weather Service expects highs to run 10 to 20 degrees above normal through Wednesday, with Monday reaching near 94°F under full sun. An upper-level ridge is anchoring high pressure off the Mid-Atlantic coast, locking in a warm south-to-southwesterly flow for several days. Plan strenuous outdoor activity for early morning, stay hydrated, and check on neighbors who may not have air conditioning.
Phillies vs. Reds at Citizens Bank Park
The Philadelphia Phillies open a three-game home series against the Cincinnati Reds on Monday, May 18, running through Wednesday, May 20. Monday’s game is pure summer baseball — near 94°F and sunny. Conditions ease slightly mid-week, but a cold front may push storm chances into Wednesday evening, so watch conditions closely if you have tickets to that final game.
Dress for a hot South Philly afternoon — a Philadelphia Phillies jersey and a Philadelphia Phillies fitted cap will have you repping the team and staying comfortable. Still need seats? Get tickets on SeatGeek or Find tickets on StubHub.
What To Wear
Sun protection is non-negotiable this week. The UPF 50+ Fishing Shirts for $6.50 deal on site is excellent for the ballpark, trail, or backyard. If you’re teeing off at one of the area courses, the Men’s Golf Shorts at $14.85 are worth grabbing while the sale lasts.
Tonight & Dinner
Sunday evening stays warm and pleasant — low around 67°F with partly cloudy skies and a light southwest wind. If you’re looking for something to do tonight, August Burns Red and The Amity Affliction bring their Springs Horizons Tour to The Fillmore Philadelphia. For dinner at home, a light pasta or stir-fry is a perfect fit for a warm night. Set up a badminton set in the backyard before dark and make an evening of it. Need ingredients? You can order groceries on Amazon and have everything for tonight’s dinner delivered to your door.
Next Few Days
- Monday: Sunny, high near 94°F — peak heat of the week
- Tuesday–Wednesday: Low-to-mid 90s continue, well above normal
- Wednesday night–Thursday: A cold front arrives with chances of showers and thunderstorms
- Late week: Temperatures finally moderate back toward seasonal norms
Stay current with the Philadelphia weather forecast as storm timing Wednesday could shift. It’s a week worth watching closely — and a good one to browse outdoor gear deals before the heat peaks.
