Phoenix woke up to a mild Wednesday, May 20, with Sky Harbor reporting about 70°F around 5:35 a.m. The cool start will not last long. Sunshine will take over and send Valley temperatures into the low 90s by this afternoon, with overnight lows only dropping into the upper 60s to low 70s. If you have outdoor plans, try to schedule the heavy lifting for morning or evening hours and keep water close.
Afternoon Heat Through The Weekend
Sunny, dry weather is locked in through the holiday weekend. Highs are expected to reach around 93°F on Wednesday, climb into the mid‑90s on Thursday and Friday, and edge toward 100°F by Sunday, with roughly 101°F possible on Memorial Day (Monday, May 25). South to southwest winds should stay light, around 0–5 mph, with the usual bump in afternoon breeziness, according to NWS Phoenix.
Heat Relief And Safety
Maricopa County’s Heat Relief Network has cooling centers, hydration stations and extended library hours open for the season. If you need a cool place or a hand getting there, call 2‑1‑1 or look up nearby options on the Heat Relief Network map.
Fire Weather And Lightning Risk
Looking into early next week, the forecast discussion notes a slight chance of isolated storms and dry lightning over eastern Arizona’s high terrain, with Monday currently the most favored day for any activity. Any lightning that does develop is expected to produce little measurable rain. With afternoon humidity dipping into the single digits to low teens and only modest overnight recovery, dry lightning could spark new wildfire starts in remote areas, the NWS notes. If you are planning backcountry travel, monitor updates and skip campfires or any other ignition sources.
Plan Ahead
For holiday weekend plans, avoid heavy outdoor labor between late morning and mid‑afternoon, stay hydrated, and keep an eye on any changes in the winds. We will post updates if watches or advisories are issued.
