 Mostly clear skies as the sun rises over the Potomac River near the Arlington Memorial Bridge on Sept. 11. (Jeannie In D.C. via CWG.news/Photos Flickr) | Today's daily digit A somewhat subjective rating of the day's weather, on a scale of 0 to 10. 5/10: Humidity may not build in earnest until late in the day, so there's arguably a bit less bite to highs near 90. Express forecast - Today: Turning hotter, slowly more humid. Highs: Upper 80s to low 90s.
- Tonight: Partly to mostly clear, a bit muggy. Lows: Mid-60s to low 70s.
- Tomorrow: Partly to mostly sunny, humid. Highs: Low-to-mid 90s.
Forecast in detail We do seem to be starting a stretch of several days near or past 90 degrees. A "late-season" heat wave perhaps, but we've been seeing more of these in September over the past decade. Humidity builds late today and sticks around for much of the week as well. Get ready to sweat again! Get our daily forecasts on your Amazon Alexa device. Today (Sunday): A few clouds and some haze is possible but skies are generally bright, though perhaps not all that blue. Highs in the upper 80s to low 90s are noticeably above average. Humidity starts to rise, but fortunately does so rather slowly. So the morning should still feel fairly comfortable, but feeling more humid by afternoon as dew points rise into the low-to-mid 60s. Winds are mostly light from the southwest, but could occasionally gust near 20 mph during the afternoon. Confidence: High Tonight: Partly to mostly clear and getting more humid. With higher, more uncomfortable dew points rising through the mid-60s, overnight lows won't drop much (thanks to the insulating atmospheric moisture). Mid-60s to low 70s are about as low as we can go before dawn. Light winds from the southwest may go nearly calm by sunrise. Confidence: High Follow us on YouTube, Facebook, Twitter and Instagram for the latest updates. Keep reading for the forecast through midweek… Tomorrow (Monday): Heat and humidity continue to build over our region. High temperatures eye the low-to-mid 90s. And with high humidity (dew points rising to near 70), the heat index could reach near 100. Otherwise we're partly to mostly sunny, with perhaps a bit of haze too, and only the slightest chance for a shower or stray storm. A light wind blows from the west. Confidence: Medium-High Tomorrow night: Humidity rises toward its peak level of the week, with dew points in the sultry near 70 to low 70s range. Skies are partly cloudy and breezes should stay light. Low temperatures may only bottom out in the upper 60s to mid-70s. A brief shower or sprinkle is possible nearer dawn, too. Confidence: Medium-High A look ahead Skies continue partly to mostly sunny Tuesday and Wednesday, again with some haze possible, and with slight shower and storm chances each day. Highs top out in the upper 80s to mid-90s. Light to moderate breezes from the south and southwest continue to keep us socked in with moderate to high humidity (dew points in the mid-60s to near 70). Confidence: Medium-High Read more about Capital Weather Gang's confidence rating. | 
