Most of the time the first week of March is very light crowds, except during years when Mardi Gras falls during that time which can increase the crowds a bit.

Some tips for traveling in March:

• Traveling to Disney World during a busier time means you have to be extra diligent about having a good touring plan. As long as you're zigging while other people zag, you'll do fine.
• Most people visiting Disney World in March will want to pack summer clothes since it's usually hot, but make sure you have a jacket because it can be cool, especially in the early morning and at night. Check the forecast before you leave to verify.