Summer shade. (Josh Lorenzo via Flickr)

* Code orange air quality alert Monday — unhealthy air for sensitive groups *

TODAY’S DAILY DIGIT
A somewhat subjective rating of the day’s weather, on a scale of 0 to 10.

4/10: A Monday with hot, stagnant air. Can we spin again?

EXPRESS FORECAST

Today: Mostly sunny, hot. Highs: 89-93.
Tonight: Mostly clear. Lows: 67-74.
Tomorrow: Mostly sunny. Highs: 88-92.

View the current weather conditions at The Washington Post headquarters.

FORECAST IN DETAIL

We bake for three more days before a welcome breath of fresh Canadian air. Some showers may sprint through the region during the transition but, for a second straight week, conditions are mostly dry all week long. The cooler, less humid air arriving Thursday into Friday and lasting through the weekend may start to retreat by Labor Day, when it turns hotter again.

Today (Today): Much like Sunday, ample sunshine steadily heats the air. Most places see highs with a few degrees of 90 and it’s moderately humid. With high pressure directly overhead, there’s not much breeze — hence the air quality concern. Confidence: High

Tonight: It’s a mostly clear, still, summer evening. Overnight lows range from the low to mid-70s downtown to the upper 60s in our cooler suburbs. Confidence: High

Follow us on Facebook, Twitter, and Instagram for the latest updates. For related traffic news, check out Dr. Gridlock. Keep reading for the forecast through the weekend …

Tomorrow (Tuesday): Abundant sunshine brings more summer swelter as highs make another run toward 90. The humidity is noticeable but not the worst we’ve felt this summer. There’s not much of a breeze, so shade is your friend. Confidence: Medium-High

Tomorrow night: Skies are clear to partly cloudy and it’s muggy. Overnight lows range from the upper 60s to low to mid-70s downtown. Confidence: Medium-High

A LOOK AHEAD

Wednesday is probably the last day we hit 90 this week before a cold front comes in late in the day or overnight. This front may (30-40 percent chance) set off some widely scattered showers and storms, most likely in the evening or overnight, when lows are near 70. A shower or two may linger Thursday morning, before it becomes partly sunny with highs in the mid-80s. The cooler air behind the front may not become apparent until Thursday night, when lows dip into the low to mid-60s downtown and perhaps upper 50s in our cooler suburbs. Confidence: Medium

Friday through Sunday look magnificent. High pressure builds in from the northwest, delivering sunshine, less hot temperatures and much lower humidity (dew points in the 50s maybe creeping up to near 60 Sunday). Highs Friday and Saturday are in the low 80s, warming to the mid-80s on Sunday. Overnight lows are mostly in the 50s to the low 60s downtown. Confidence: Medium

Labor Day turns a little toastier — with highs 85-90. We should be dry; the only wild card is what happens to moisture from the tropical system moving inland from the gulf coast states into the Southeast. We’ll watch that carefully. Confidence: Low-Medium

SNOW POTENTIAL INDEX
A daily assessment of the potential for at least 1 inch of snow in the next week, on a 0-10 scale.

0/10 (→): Hi. Sending some cool thoughts. Don’t forget about me …