Border Crossing Seasonality: When to Book and Pad

Why this matters. At Nogales, the BTS truck count for May runs at 134.3% of an average month. In September it runs at 67.2%. A quote that treats those two months alike is wrong in one of them, and you only find out at the gate. For a 5 to 15 truck fleet that crosses a few times a week, the month you book can change the idle time you absorb.

What the index says

For each year from 2022 to 2025, every month is divided by that year's monthly average. The four years are then averaged. 100% is an average month at that port, and 112% means the month usually carries about 12% more trucks. In the last 12 months, 12,797,830 trucks entered across all land ports, which is -1.2% against the 12 months before.

Five ports, five calendars

There is no single border season. The busiest month at Laredo is March. At Otay Mesa and Santa Teresa it is October. At Nogales it is May.

Source: BTS Border Crossing/Entry Data, measure Trucks inbound, last 12 months Sep 2025 to Aug 2026; index uses 2022 to 2025. Swing is busiest minus quietest, in points.

Laredo is the largest port and one of the flatter ones. Nogales is smaller and swings by 67.1 points. The larger the swing, the more a flat allowance for crossing time will miss. At the 30 busiest ports, the busiest month typically runs at 109.1% of an average month (median).

One port, twelve months

Here is Laredo for the whole year, from the same snapshot. Ten of 12 months sit within 6 points of average. March, May, August and October are the ones above 104%.

Computed from the BTS snapshot with the method on the planner page. The page lists the busiest and quietest month; the other ten are computed.

Turning an index into idle cost

The planner turns an index into minutes with a rule you control: extra wait = your usual wait x sensitivity x (points above 100%) / 10. Cost = extra minutes / 60 x idle cost per hour x crossings. The sensitivity is a guess. It says how many percent more waiting you assume for each 10 points of extra volume.

Invented inputs, the planner's pre-filled values: usual wait 45 minutes, sensitivity 10%, idle hour $85. Not a measured wait.

The totals look small for one month. The point is the ratio. Nogales in May carries about 6 times the extra idle cost of Laredo in October on identical assumptions. If your sensitivity is 20% and not 10%, the Nogales figure doubles to $349.86. Your own crossing log is what turns the guess into a number.

The pattern is not the trend

The index tells you which month is busy. It does not tell you whether the port is busier than a year ago. Volume itself moved a lot at some ports in the last 12 months: Santa Teresa +16.0%, Del Rio +21.4% and Progreso +39.6%, against Port Huron -8.6% and Sumas -14.0%. Laredo is +0.1% and Detroit +3.6%. A port that grew by a fifth may run a busy month harder than the old index suggests, and a port that shrank may run it lighter. Read the index for the month and the change column for the year.

Below 100% the planner's formula adds nothing. At Nogales in September, at 67.2%, the extra wait is zero and your usual wait stands. That is also the month to ask whether a slow crossing is the port, or your own paperwork.

How to use it when booking

• Look up your port, not the national story. Detroit peaks in March and Santa Teresa in October.
• Loosen the delivery window in months above 110%. That is a month to quote with a longer crossing allowance.
• Keep a crossing log. Date, arrival and release time. After a quarter you hold the wait pattern this dataset cannot give you.
• Check the accessorial terms. Idle hours can only be billed if the rate confirmation allows it. See the detention pay guide.
• Re-check each quarter. A new trade rule or a lane closure can break a pattern.

Common questions

• Does a busy month mean longer waits? Not by itself. Waits depend on inspections, staffing, lanes open, weather and paperwork as well as volume.
• Why 2022 to 2025? The 2020 and 2021 pandemic years bent the pattern and 2026 is not a full year yet.
• How current is it? The snapshot runs through Aug 2026 and BTS can revise recent months.

The border seasonality planner has all 30 ports, a map and the calculator with your own wait and idle cost. To see whether idle time at the border ever reached an invoice, send us your last 20 loads.