You can Metro from DCA to McPherson Square which is 2 blocks from the St Regis without having to change trains. Get on the BLUE Line at DCA in the direction of Addison Road/Seat Pleasant (important). Get off at McPherson Sq and take the Vermont Ave exit (not 14th St). At the top of the escalators, make a U-turn, then make a left onto I St and a right onto 16th St. The St Regis is on the right at the corner of 16th and K. Depending on travel times, Metro should cost you anywhere from $1.35 to $1.70 and take about 20 minutes. Cab will be faster and it'll set you back about $18.

We've been having very pleasant weather this week (cool mornings in the 60s and highs of 80s). The only thing to worry about on Sunday is rain and nasty storms!