The traffic congestion calendar is emerging from a winter lull. This is a very busy weekend for events that could slow the pace of travel in the D.C. region.

The prime culprit is the Rock ’n’ Roll Marathon, an annual event that takes runners through many of the District’s neighborhoods on Saturday between 7 a.m. and about 2 p.m. Start times have been adjusted this year because of Metro’s policy of not opening early for special events.

While St. Patrick’s Day isn’t till next Friday, this weekend is the time for St. Pat’s parades. And despite the chill, many people are likely to be around the Tidal Basin and the Mall to see how the cherry blossoms are advancing.

The Capital Weather Gang tells us to expect more sun than clouds on Saturday, but it will be breezy and chilly, with a high temperature in the mid-30s. We’ll have more sunshine Sunday, and the temperature will be slightly warmer, in the upper 30s to low 40s.

Don’t forget to spring the clocks forward. Daylight saving time begins at 2 a.m. Sunday.

Sporting events: The Big Ten Men’s Basketball Tournament continues through the weekend at Verizon Center. Watch for extra congestion in the Gallery Place-Chinatown Metro station and on the streets around Verizon Center.

If you’re planning to take transit to any of these events, check the schedule of Metrorail maintenance disruptions below. But first, let’s review the big event, the Saturday marathon.

Rock ’n’ Roll Marathon
The marathon and the half-marathon start at Constitution Avenue and 14th Street NW. The marathon begins at 7 a.m. and the half-marathon at 8:30 a.m. Far more people sign up for the half-marathon, and the late start means participants can take Metrorail, which opens at 7 a.m., but they should check the train timetables. Both events end at RFK Stadium. A 5K course begins and ends at RFK, with a start time of 8 a.m. The nearest Metro station to the Constitution Avenue start is Federal Triangle. The nearest to RFK is Stadium-Armory.

The map below shows the routes for the marathon, half-marathon and 5K run. The event is likely to have a high impact on streets in neighborhoods that include Capitol Hill, Adams Morgan, Columbia Heights, Southwest Waterfront and Anacostia. Driving on the South Capitol Street and East Capitol Street bridges also will be affected. Here is the D.C. police department’s list of street closings.

The event sponsors are in a new partnership with Waze, the travel guidance app. Waze will incorporate the street closing schedule into the app. Its alerts and push notifications will offer alternative routes, parking options and information on detours and traffic congestion.

The sponsors have a discount deal with the SpotHero parking reservation service, so drivers can look for off-street parking within walking distance of the start line. Also, there will be a runner drop-off point at 14th Street and Independence Avenue SW, which is about three-tenths of a mile from the start.

At RFK, reserved parking is available in Lots 6 and 7 for $16.50 per car. The sponsors arranged for a shuttle bus service from RFK to the start line, but that’s by reservation only, and the seats are now filled.

The D.C. Streetcar will suspend Saturday service along H Street and Benning Road NE until the marathon passes, about 1 p.m.

D.C. Circulator will modify two bus routes on Saturday. The Mall route will delay opening until 10 a.m. The Woodley Park-Adams Morgan-McPherson Square route will detour around its stops near Harvard Street NW. Buses will turn back at Florida Avenue NW between 7 a.m. and noon.

On Saturday and Sunday, Metrorail opens at 7 a.m. and closes at midnight.

Red Line. Trains will share a track between Silver Spring and Forest Glen while crews work on preventive maintenance projects. Trains are scheduled to leave the ends of the line at Shady Grove and Glenmont every 15 minutes. From 9 a.m. to 9 p.m. Saturday and Sunday, more trains will be in service between Shady Grove and Rhode Island Avenue, so in that zone, trains should reach platforms every six to eight minutes.

Blue Line. The SafeTrack maintenance project affects service on the Blue and Yellow lines. Blue Line trains share a track between Braddock Road and Van Dorn Street, with trains operating every 24 minutes.

Yellow Line. Trains are scheduled to operate every 24 minutes between Huntington and Mount Vernon Square, sharing a track between Braddock Road and Huntington. More trains will be in service between Reagan National Airport and Mount Vernon Square.

Silver Line. The trains will operate on their regular weekend schedule, but only between Wiehle-Reston East and Stadium Armory. Crews will work on communications cables at Largo, the line’s normal eastern terminal. This weekend, only the Blue Line will serve Largo.

Orange Line. Regular weekend service.

Green Line. Regular weekend service.

Four Courts Four Miler
The annual Four Courts Four Miler run is scheduled for 9 a.m. to about noon Saturday starting in front of Ireland’s Four Courts Pub, near the Court House Metro station at 2100 Wilson Blvd. in Arlington. See a map of the course, which includes the locations of nearby Capital Bikeshare stations.

Arlington County police plan these closings: Wilson Boulevard from Courthouse Road to North Rhodes Street, 6:30 to 11 a.m.; Wilson Boulevard from Route 110 to North Courthouse Road; and northbound Route 110 from I-395 to I-66, 8:45 to 11 a.m.

Street parking in the area will be restricted. Watch for temporary “No Parking” signs. Metrobuses will detour from Moore Street west onto Wilson Boulevard and north on Nash Street back to their regular routes during the event.

Manassas St. Patrick’s Day Parade
The parade through Old Town Manassas is scheduled for 11 a.m. to 2 p.m. Saturday. See a map of the parade route, which includes parking areas.

D.C. St. Patrick’s Day Parade
The District’s parade starts at noon Sunday from Constitution Avenue NW at Seventh Street, then the marchers, floats and bands proceed west along Constitution to 17th Street NW, wrapping up at about 2:30 p.m. The nearest Metrorail stations are Federal Triangle, Archives and Smithsonian. Make sure you update your clocks to daylight saving time for this one.

Looking ahead …
The National Cherry Blossom Festival starts Wednesday, five days earlier than originally scheduled. The latest prediction from the National Park Service on the peak bloom is March 19-22. But watch for pedestrian and auto traffic to build around the Tidal Basin this coming week.