| Yellowstone Visitation | 2010 | 2009 | Change |
| January | 25,595 | 24,770 | + 3.3% |
| February | 29,108 | 28,355 | + 2.7% |
| March | 21,028 | 17,317 | + 21.4% |
| April | 32,763 | |24,831 | + 31.9% |
| May | 250,445 | 261,763 | - 4.3% |
| Total Year-To-Date | 358,939 | 357,036 | + 0.5% |
Most of the park is inaccessible by automobile during the winter and early spring. May represents the first month most major park roads are open to wheeled visitor traffic and when visitor services begin to reopen for the busy summer season.
While May visitation is off slightly compared to 2009, it remains the fourth highest on record. There have been just four occasions where visitation to the park for the first five months of the year was higher than that recorded in 2010.
The winter and spring seasons represent a small but important portion of the park’s annual visitation, which topped the 3 million mark the last three years, including an all time record of nearly 3.3 million visitors in 2009.
In comparison, as many people will visit the park during two weeks in July as typically enter during the entire first five months of the year.
