The Busy Season
See when visits rise and fall at 13 national parks.
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How to explore
Park visits rise and fall through the year. This project shows how that calendar differs across 13 national parks and how it has changed since 1979.
Choose a park
Start with Indiana Dunes, then choose another park to see a different seasonal pattern.
Compare decades
See what share of visits fell in each month during the 1980s and during 2016–2025.
Choose a year
Follow one year through the monthly grid and the annual visit line.
Compare parks
See which parks packed the largest share of visits into their three busiest months.
- Recreation visit
- One person entering a park for recreation; the same person can count more than once.
- Monthly share
- The percentage of a year or period's visits that happened in one month.
- Peak month
- The month with the largest number of recreation visits in the selected period.
- Three-month share
- The percentage of visits in a park's three busiest months, whether or not those months are next to each other.
13 national parks · 1979–2025
The busy season
See when visits rise and fall at 13 national parks.
These are monthly recreation-visit estimates. They show the rhythm of visits, not how many people were inside a park at one time.
Start here
Choose a park
Start with Indiana Dunes, then choose another park to see a different calendar.
01 / Compare decades
How do visits change through the year at Indiana Dunes?
Each bar shows a month's share of all visits in its ten-year period. Percentages make the seasonal shape comparable even when total visits changed.
July remained the busiest month in both periods. These estimates do not tell us why travel changed.
Read every monthly share
| Month | 1980–1989 | 2016–2025 |
|---|---|---|
| January | 2.2% | 3.0% |
| February | 2.2% | 3.4% |
| March | 3.6% | 5.3% |
| April | 6.2% | 5.5% |
| May | 11.0% | 9.2% |
| June | 16.2% | 14.8% |
| July | 19.6% | 18.5% |
| August | 16.7% | 15.3% |
| September | 9.6% | 10.5% |
| October | 7.4% | 7.1% |
| November | 3.3% | 4.0% |
| December | 2.1% | 3.4% |
02 / Choose a year
Was every year alike?
Choose a year to connect the monthly pattern with the annual total. The grid keeps each year on one row; brighter squares mark months with a larger share of that year's visits.
Select any row to update the year above and the long view below. The 2020 and 2021 rows include closures and other pandemic-era disruptions; they remain in the record.
Annual recreation visits
The line connects each year's total estimate. It shows scale and interruption, but it cannot separate real travel changes from revisions to park boundaries or counting methods.
03 / Compare parks
Which parks have the shortest busy season?
The bar is the share of 2016–2025 visits that fell in each park's three busiest months. A longer bar means visits were packed into a smaller part of the year. Choose a park to take it back through the charts.
Among these parks, Denali has the most concentrated recent season at 77.5%. Grand Canyon has the least concentrated at 34.1%. This compares timing, not crowding or park capacity.
Why this exists
The question
How has the share of visits in each month changed at 13 national parks since 1979, and which parks still have the most concentrated seasons?
What to try
Choose a park, compare two ten-year periods, then choose a year and follow it through the monthly and annual views.
Method and limits
About the data
I downloaded the National Park Service Visitor Use Statistics Data Package, 2025 from its Data.gov record on September 22, 2026. The package was published March 26, 2026 under CC0. I verified the 72,212,002-byte CSV against SHA-256 284ab33b15e9a817948cba4663ed33748ba24dbbc36b750be2b2cfbb662fe912, then retained the TRV recreation-visit statistic for 13 named parks. Every park has all 12 published monthly values for each year from 1979 through 2025, giving 7,332 retained values from 2,905,440 source rows. The checked-in Python reduction produces the 73,771-byte static snapshot deterministically. Monthly shares divide a month's visits by the total for its year or ten-year period. The three-month measure sums the three largest monthly shares. The two era views use 1980–1989 and 2016–2025 so both cover ten complete years. Published zeroes and the pandemic years remain in the data. Recreation visits are estimates of entries, not unique visitors or people present at once. Local counting procedures, park boundaries, access, closures, and reporting can change, so comparisons cannot by themselves explain why a pattern changed or measure how crowded a place felt.
Skills used
- Data analysis
- Data engineering
- Statistical reasoning
- Information design
- Interaction design
- Visual design
- Editorial storytelling
- Accessibility
- Performance
What the data shows
- Twelve of the 13 included parks had a smaller share of visits in their three busiest months in 2016–2025 than in 1980–1989. Acadia was the exception, rising from 52.3% to 58.4%.
- Zion had the largest decrease in three-month concentration among the included parks, from 49.6% in the 1980s to 35.5% in 2016–2025.
- For 2016–2025, Denali had the most concentrated season among the included parks at 77.5%; Grand Canyon had the least concentrated at 34.1%. These percentages compare timing, not crowding or capacity.