Taking metro in Washington DC

If you mean the JW Marriott on Pennsylvania Avenue, then it's only 3/10 of a mile from the Federal Triangle Metrorail stop, which shouldn't take more than 7 minutes. Yes, it's safe to walk there. But the metro is operating at reduced capacity now so the wait for a train may be longer than expected depending on your luck.

Google Directions (sorry for long link):
https://www.google.com/maps/dir/Federal+Triangle+Metrorail+Station,+12th+Street+Northwest,+Washington,+DC/JW+Marriott+Washington,+DC,+1331+Pennsylvania+Avenue+NW,+Washington,+DC+20004/@38.8951976,-77.0320738,17z/data=!3m1!4b1!4m13!4m12!1m5!1m1!1s0x89b7b7998b323347:0x4887a558338ffab8!2m2!1d-77.0283286!2d38.893788!1m5!1m1!1s0x89b7b7979cdd8be3:0x79b949ea780c8702!2m2!1d-77.0316355!2d38.8965989

PS. You can also get off at the Metro Center station (also very close - 5 min walk), but it has multiple exits and may be more confusing. The Federal Triangle station is easier to navigate.

Assuming you are flying into Reagan-National Airport (DCA) rather than Dulles (IAD), you'll have a choice of the Blue Line or the Yellow Line toward town. The Yellow line is more direct (only 12 minutes), but it doesn't get you closer to your hotel than the Archives-Navy Memorial stop at 7th and Pennsylvania Avenue. It's an easy but not super-short (roughly 1/2-mile) walk from there to the JW Marriott. You'd basically follow Pennsylvania Avenue west and then cross Freedom Plaza. I agree with Agnes that there shouldn't be any issue with walking in that part of town.

The Blue Line takes a meandering route into the city but will drop you at either Metro Center or Federal Triangle, both of which are considerably closer to your hotel.

Alternatively, you could start out on the Yellow Line and transfer to the westbound Blue or Orange Line at L'Enfant Plaza or to the westbound Red Line at Gallery Place-Chinatown. The Blue and Orange lines stop at both Federal Triangle and Metro Center. The Red Line stops at Metro Center. Unfortunately, both the L'Enfant Plaza and the Gallery Place-Chinatown stations have a potential to be confusing. You surely don't have any mobility issues, so I don't think it's worth the hassle of planning a Metro transfer, especially late in the day and encumbered by luggage.

Since the elapsed time between trains is longer than usual right now, in the absence of special circumstances (like a downpour) I'd look at the projected train-arrival times shown on the electronic signage Metro airport station and take whichever train looked like the best option, time-wise.

The Blue line would mean a longer ride, but you might end up with a substantially shorter wait for a Blue Line train. It's worth mentioning that the Metro platform at the airport is open-air. If it's cold the night you arrive, you might be more comfortable sitting on a Blue Line train than hanging out on the platform waiting for a Yellow Line train.

If you are arriving at Dulles Airport, post again!

Thanks Agnes. I am staying at that Marriott. How is it taking Uber in DC? They can be hard to book in the Los Angeles area lately.

I don't use Uber, so I can't comment. Pre-covid, I took the metro extensively and at all hours.

Thanks acraven!
I am going to visit my uncle in Virginia after the race. He does not like to drive in the city. He lives out by Dulles Airport and said he could pick me up there. Can the metro take me from near my hotel to Dulles?

The Metro takes you part of the way, as far as the Wiehle-Reston East Station on the Silver Line (accessible from either Metro Center or Federal Triangle), then you hop on a bus. The WMATA website says Silver Line trains are only running every 30 to 40 minutes at the moment. There are two bus options for the second leg. I've never take either, but the fastest seems to be the Silver Line Express, which runs every 15 to 20 minutes and takes about 15 minutes at a cost of $5 (in addition to the cost of the Metro; I assume you can pay with a Metro farecard; I'm almost certain the driver will not make change if you pay in cash. The other bus option is the Fairfax Connector 981, which departs from Bay K at Wiehle-Reston East; I believe it is less frequent and less expensive as well as slower than the Silver Line Express (taking about 30 minutes). This 981 schedule is dated 2015, but I don't see a later one online: https://www.fairfaxcounty.gov/connector/sites/connector/files/assets/documents/pdf/routes/981-983.pdf

Alternatively, you could do as I do when I'm flying out of Dulles: Take the 5A express bus from outside the L'Enfant Plaza Metro Station (on the Blue, Orange, Yellow and Silver Lines) all the way to the airport. The run is scheduled to take roughly an hour. The bus costs about $7, I believe; don't expect change from the driver if you pay in cash rather than using a Metro farecard. The bus departs just a few feet from the D Street Metro station exit. There's signage in the station, but there are three exits, and getting to the right one isn't a piece of cake. I see that the bus is currently scheduled to run considerably less frequently than it used to--perhaps due to COVID.

Under normal circumstances the Metro + shuttle bus would [edited] probably be faster. With the current Metro limitations, I'm not sure. It's not uncommon for the 5A bus to depart somewhat late. I've never run into really significant traffic delays in either direction, but no matter what choice you make here, it's going to be difficult to predict when you'll finally reach Dulles Airport.

Dulles is way out of town. A taxi would be very costly; I'd guess over $70.

Thank you!