Home / Methodology

Methodology

Every number on this site comes from a government count and a calculation you can follow. Nothing here is a forecast.

Airports

Source

The US Transportation Security Administration publishes weekly "throughput" files that count the passengers screened at each airport checkpoint, by hour. We use 17 weekly files covering 119 days between May 10, 2026 to October 10, 2026.

What we calculate

• We add up every checkpoint at an airport to get one passenger count per hour.
• For each airport we average those hourly counts across the days in the data, separately for each day of the week.
• The busiest hour is the hour with the largest share of an average day's passengers. The busiest three hours are the three consecutive hours with the largest combined share.
• The lightest hour is the hour with the smallest share between 6 am and 10 pm.
• Hours are local airport time. We checked this by confirming that airports in different time zones peak at similar local hours.
• We checked our daily totals against the national daily checkpoint numbers TSA publishes on its passenger volumes page. Ours come to between 97% and 100% of TSA's figure on all 119 days. The gap is steady from day to day, which means no hours were dropped in the processing.

Limits

• These are counts of people screened, not wait times. The data holds no timings, so we make no claim about how long a line takes.
• The files cover May 10, 2026 to October 10, 2026 only. TSA's reading room does not list June 14, 2026 to July 18, 2026, so those days are missing. Winter and the main holiday periods are not shown.
• Only airports with complete coverage of every day and at least 4,000 people screened a day get a page. Smaller airports are left out.
• Counts can differ from an airport's own passenger figures because they cover people screened at security checkpoints, not everyone who uses the airport.

National parks

Source

The US National Park Service publishes recreation visitor counts by park and month in its visitor use statistics system. We use all 63 national parks, 2015 to 2025.

What we calculate

• For each year, each month's visits are divided by that year's total, giving a month's share of the year.
• We average those shares across years. 2020 and 2021 are left out because pandemic closures changed the usual pattern. A year is used only when all 12 months are present.
• The busiest month has the highest average share. The quietest month overall has the lowest.
• The quietest open month is the lowest month that still draws at least 4% of the year's visits. Months below that line often mean snow, closed roads or reduced services, so we flag them rather than recommend them.

Limits

• The counts are monthly, so they cannot show a particular week, a holiday weekend or a day of the week.
• A low-visit month is not automatically a good month. Heat, cold, smoke and closures all matter. Check the park's own conditions page.
• Park totals include everyone counted at the park, not only people at its busiest viewpoints, so a quiet month can still feel busy at the famous spots.

General

All figures are history. Conditions change, so confirm with the airport, the airline or the park before you travel. We rebuild the pages when new government data is published.