The Rodriguez family, of Orlando, Fla., cool off in a fountain last summer. (Bill O'Leary)

It’s afternoon and the temperature reads 96 degrees at Reagan National Airport. This makes things official: It’s not even June 1, and the face-melting, humid weather season we love so much here in D.C. is already upon us.

We can have fun with the heat, but it can be a serious threat to children, the elderly, or pretty much anyone with a compromised health. From last July: heat-related deaths can almost always be prevented. The Centers for Disease Control gives you a good tipsheet on what to do, or not.

Here’s the rundown:

TEMPS: Before the day is done, temperatures will creep toward the upper 90s, but humidity will make it feel like it’s anywhere from 100 to 105 degrees, according to the Capital Weather Gang roundup. There’s a heat advisory for the area until 8 p.m.

AIR: On top of ghastly temps, it’s a Code Orange air quality day, which means people with respiratory problems or other sensitivities should think twice before spending much time outside. (If you heard the rumbling of garbage trucks earlier than usual today, it’s because workers were trying to complete their rounds while avoiding air quality issues.)

COOLING DOWN : Unfortunately, the pools that were jammed over the holiday weekend won’t open for happy hour-type cooling until June 21. If it’s an emergency and you or someone you know needs a safe space, here’s a map of cooling centers around the District:

View D.C. Cooling Centers in a larger map

(* Seniors needing other services should call Barney Senior Services, lead agency for Ward 1 at 311 or 202-724-5622.) Prince George’s County has also opened up cooling centers; a list is here.

• COMMUTING: Dana Hedgpeth paints this portrait of Metro as temperatures creep up. Sound familiar?

Hot stations and rail cars are already leaving some riders drenched in sweat. Tourists with cameras around their necks crowd around fare machines trying to figure out which pass to buy. And open-toed sandals and flip-flops are making their appearance, sometimes getting caught in Metro’s balky escalators.

Tell us how you know it’s summer on Metro here.

YOU KNOW IT’S SUMMER IN D.C. WHEN ...: Finish the sentence by using #DCHeatIs and we’ll post some of your responses here.

In the meantime, check out weather updates from local Twitter sources: