Washington, D.C. is a great place to go anytime of year. The summers can be hot and muggy, especially in July and August. Although you might need a jacket anytime between April and June is cooler and much more bearable. The city also looks amazing under a blanket of snow December to February, if you can handle cold weather.
When to Visit
Most attractions are outdoors so go while the weather is bearable to explore the sites. March through May is a beautiful time to visit D.C. is March if you like mild weather and blooming plants. But it is also one of the busiest. September to November is also a gorgeous time to visit with the leaves changing colors and less tourists.
The nation’s capital is known for having one of the safest and cleanest public transportation systems in the US. The DC metro will take you to almost all of the popular tourist destinations with fares ranging from $1.85 - $6.00 depending on the time of travel. Other transportation options include walking or driving (but parking can be difficult).