What should I pack for Washington DC?

Your feet will decide whether you enjoy DC or endure it. The National Mall looks walkable on a map, but the distance from the Capitol steps to the Lincoln Memorial is about 3 km of unshaded concrete and gravel paths. Most first-timers hit 15,000-20,000 steps on day one alone, and that's before crossing to Arlington National Cemetery over the Memorial Bridge. Bring broken-in walking shoes with real arch support. Trail runners work. Fashion sneakers do not. The gravel paths around the Washington Monument will grind through thin soles by afternoon, and you'll feel every paving seam on the long walk past the Reflecting Pool. In summer, the heat radiates off the stone and asphalt until the ground feels warm through your shoes even at 7 PM.

August in DC is a specific kind of miserable. Temperatures sit between 28-35°C most days, but the humidity is the real problem. It currently reads 77% and tends to climb higher by midday. You'll feel damp within 15 minutes of leaving any air-conditioned museum. Pack 3-4 moisture-wicking shirts and change midday if you can get back to your hotel. A light long-sleeve layer is still worth carrying because the Smithsonian museums, the National Gallery of Art, and Metro cars all crank the AC to around 20°C. The temperature swing from 34°C outside to 20°C inside the National Museum of Natural History will give you a chill if you're sweat-soaked. Afternoon thunderstorms roll through 40-50% of summer days, sometimes hard enough that the open-air monuments empty out in minutes. A packable rain shell beats an umbrella here because you'll want both hands free for bags at museum security checkpoints.

Every Smithsonian museum and most government buildings run bag screening at the entrance. The lines move faster with a small daypack than a large backpack. Keep a clear or mesh pouch for your phone, wallet, and portable charger so you can pull it out quickly. That charger matters more than you'd think. Google Maps drains battery fast when you're navigating the Metro system between Foggy Bottom, L'Enfant Plaza, and Smithsonian stations, and finding a public outlet on the Mall is nearly impossible. DC uses standard US Type A/B plugs at 120V, so international visitors need an adapter. One more thing worth noting: the dress code in DC is looser than people expect. Shorts and t-shirts are fine at every monument and museum, including the Capitol Visitor Center and the Washington National Cathedral. The White House tour is the only attraction that asks visitors to avoid flip-flops and very casual clothing.

Skip packing sunscreen and basic toiletries. A CVS sits within 3 blocks of nearly every Metro station in the District, and the one at Dupont Circle stays open until midnight. Neutrogena SPF 50 runs about $12 there. You might also hold off on an umbrella. The pop-up vendors along the Mall sell them for $5-8 when rain hits, and they're one less thing through security. What you can't easily find in DC: good blister bandages (the CVS selection is limited, so bring Compeed or similar from home), a refillable water bottle with a filter (the Mall's few water fountains have a metallic taste that's safe but unpleasant), and electrolyte packets for the humidity. The tap water is drinkable but has a faint chlorine edge you'll notice if you're used to filtered water at home.