Washington, D.C. Weather Forecast: Heat Wave Timeline to 'Feels Like' 109 Degrees

Sunday will be another hot day across the region, but the larger threat will come Monday, when we could see record-breaking temperatures.

Before this heat wave is over, we'll see the heat index, or "feels like" temperature, reach 109 degrees, according to the National Weather Service.

If the actual temperature hits 100 degrees, it would be the first time since July 2012, according to The Weather Channel.

For Sunday, the main threat is coastal regions to our north and south, but the heat index in the city could reach 101 degrees — still dangerous.

But the D.C. and Baltimore areas won't get the same break on Monday.

The heat index will climb to 100 degrees by 10 a.m. and reach 109 degrees by 1 pm. Monday afternoon.

Here's a timeline for the "feels like" temperature, through Monday:

Sunday

noon: 97 degrees

1 p.m.: 98 degrees

2 p.m.: 101 degrees

6 p.m.: 99 degrees

7 p.m.: 97 degrees

8 p.m.: 94 degrees

Monday

9 a.m.: 93 degrees

10 a.m.: 100 degrees

11 a.m.: 102 degrees

noon: 106 degrees

1 p.m.: 109 degrees

2 p.m.: 108 degrees

5 p.m.: 107 degrees

6 p.m.: 104 degrees

7 p.m.: 102 degrees

8 p.m.: 98 degrees

Temperatures will cool slightly Tuesday, but it'll be some time before we feel "cool," according AccuWeather Meteorologist Kyle Elliott.

"With no strong pushes of cool air from Canada on the horizon, people from the mid-Atlantic to the Deep South can expect virtually no relief from the high heat and humidity," Elliott said.