The worst days of the year to cross are December 15–23
By Alan Scott · Who makes this · Tijuana, Baja California ·
Everyone knows December is bad. What almost nobody knows is exactly which days — and that there's a day in the middle of it all that's the emptiest of the entire year.
We measured three full Decembers, day by day.
The numbers
Each date is compared against what a normal day of that same year would be — same weekday, so "Sunday is always worse" doesn't sneak in as the effect.
| Date | vs. a normal day |
|---|---|
| December 15 | +56 min |
| December 18 | +56 min |
| December 20 | +50 min |
| December 21 | +49 min |
| December 23 | +38 min |
| December 26 | +31 min |
| December 19 | +29 min |
| December 27 | +25 min |
| December 16 | +17 min |
| December 22 | +16 min |
| December 17 | +7 min |
| December 25 | +5 min |
| December 30 | −6 min |
| December 29 | −18 min |
| December 28 | −24 min |
| December 31 | −58 min |
| 🟢 December 24 | −59 min ← emptiest day of the year |
| January 1 | −32 min |
| January 2 | +23 min ← the rebound |
December 24 is the emptiest day of the year
Nearly an hour less than a normal day. And December 31 is the same.
It makes sense once you think about it: on the day of the dinner, nobody is crossing anymore. Everyone is already where they're going to be. The people who were spending the holiday on the other side crossed on the 20th, the 21st, the 23rd — not at noon on Christmas Eve.
So if you have to cross in December and you get to choose: the 24th and the 31st are the best days of the month. By a wide margin.
Then it bounces back
The 26th is up 31 minutes, the 27th up 25, and January 2 is up 23. Same logic as any return day: everyone who crossed for the holidays comes back at once, and everyone who skipped the holiday itself crosses when things reopen.
What this data does NOT tell you
Three years per date. The pattern is strong and always points the same direction, but three is not thirty. A specific December 15 can break the mold.
It doesn't tell you the hour. Full-day averages again. We can't tell you when to leave, and we won't invent it.
And it doesn't tell you why. Christmas shopping and family visits are a reasonable explanation — but it's an explanation, not a measurement. We measured that it happens. The reason we're guessing at, same as you.
So what do you do in December
- If you can pick, cross on the 24th or the 31st. Almost an hour less.
- Avoid the 15th, 18th, 20th and 21st. They're the four worst days of the year.
- The 26th, 27th and January 2 are loaded too — that's the return.
- And the 25th is nearly normal, which is more than you'd expect.
You might also want:
- July is the worst month and January is the best
- The Tuesday after a U.S. holiday is the worst day
- Friday is the best day to cross
Sources
Data: San Ysidro, General passenger vehicle lane, northbound. SANDAG, from U.S. Customs and Border Protection records. Period: January 29, 2023 to August 8, 2026 · 1,266 days. Method: each date is compared against the median of days with the same weekday across its own full year. We use an annual baseline rather than a few-week one because a local baseline would erase the season by construction: if all of December is heavy, a "normal December" is heavy too. Retrieved: August 11, 2026.
We are not affiliated with CBP or SANDAG.
CHART · build spec
Same chart as the Spanish version — see 6_CONTENIDO/articulos/04_diciembre_los_peores_dias.md. 🔴 Do not re-derive the values.
Label translations only: dates as "Dec 15 … Jan 2", direct labels on December 24 (−59) and December 15 (+56).