Route profile
IAH→SJU
Flight reliability, delays and best times to fly from Houston to San Juan, 2,007 miles.
Right now
Aviation weather is not currently a factor.
Aviation weather is not currently a factor.
Route reliability
July 2023 – July 2026
Better than 64% of comparable major US routes (4,598 compared)
Calculated from 2,873 flights. How this is calculated · What counts as on time
IAH → SJU arrives on time 80.1% of the time; the return trip, SJU → IAH, arrives on time 84.3% of the time, a 4.2-point gap between the two directions of the same city pair.
IAH → SJU spends 26.6 minutes on the ground on a 2,007-mile trip: 21.8 minutes from pushback to wheels-up at IAH and 4.9 minutes from touchdown to gate at SJU.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
What sets this route apart
Where IAH to SJU differs most from similar routes by hour, weekday, month and airline, July 2023 – July 2026.
IAH to SJU is at its best against routes of similar length for flights scheduled at 3 PM: 84.1% arrive on time, 10.6 points ahead of the 73.5% those routes manage at that hour. Against all other routes the gap is 11.4 points.
IAH to SJU holds up on Mondays better than routes of similar length do: 84.8% on time to their 78.0%, a 6.8 points lead. Against all other routes the gap is 7.6 points.
Saturday is the day IAH to SJU slips furthest against routes of similar length, 73.3% on time where they average 79.3%, 6 points lower. Against all other routes the gap is 5.8 points.
April is kinder to IAH to SJU than to routes of similar length: 89.3% on time against 80.8%, 8.5 points better. Against all other routes the gap is 9.4 points.
IAH to SJU against comparable routes
July 2023 – July 2026| Measure | This route | Compared with | Them | Gap | Flights behind it |
|---|---|---|---|---|---|
| Hour: 3 PM departures | 84.1% | routes of similar length | 73.5% | +10.6 pts | 954 here, 46,835 there |
| Weekday: Monday | 84.8% | routes of similar length | 78.0% | +6.8 pts | 374 here, 165,701 there |
| Weekday: Saturday | 73.3% | routes of similar length | 79.3% | −6.0 pts | 468 here, 154,673 there |
| Month: April | 89.3% | routes of similar length | 80.8% | +8.5 pts | 205 here, 91,649 there |
Each comparison pools the flights of other routes, with this route’s own left out. Similar length means within 15% of this route’s 2,007 miles, with at least 5 such routes. A bucket is set against the most comparable group that has enough flights: similar length, then the same origin (at least 3 routes), then all other routes. Hours, weekdays and months appear only where both sides have 120 completed flights, and airlines where both have 600. The gap must be at least 2 points and 2 standard errors, and only the largest gap each way is kept per measure. These are differences in the flights counted, not causes.
When it goes wrong
July 2023 – July 2026
40 min late
against a median of 8 min early
Percentiles over 2,873 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at SJU after arriving from IAH.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 33% | Likely to miss |
| 45 min | 19% | High risk |
| 60 min | 12% | Some risk |
| 90 min | 6.4% | Some risk |
| 120 min | 3.9% | Low risk |
This is one leg of a connection. Gate changes and the next flight's own schedule matter too. And a connection can fail before delay is even the question — this route cancels 0.97% of the time and diverts 0.10% of the time, which a late arrival never shows up in.
Chance of missing is the share of 2,842 arrivals on this route that landed later than the connection time less 30 minutes to reach the next gate.
The worst tenth of arrivals on this route land at least 40 minutes late (90th-percentile gate arrival delay), over 2,873 operations.
Any other layover length: connection checker.
Best time to fly
IAH → SJU flights departing 9 PM–5 AM arrived on time 84.7% of the time, against 57.4% for 6–9 PM departures, a gap of 27.3 percentage points.
By departure window
By departure hour
- 12 AM to 8 AM: too few flights to score
- 9 AM: 84.7% on time from 164 flights
- 10 AM: 77.6% on time from 1,004 flights
- 11 AM to 2 PM: too few flights to score
- 3 PM: 84.1% on time from 965 flights
- 4 PM to 10 PM: too few flights to score
- 11 PM: 84.7% on time from 364 flights
Departure windows with fewer than 120 flights are not scored.
Why IAH → SJU runs late
July 2023 – July 2026
crew, maintenance, boarding and fueling, all within the carrier’s control
the inbound aircraft was late, so this flight started late
airspace and airport capacity, including weather-driven flow control
weather severe enough to stop this flight specifically
Share of the delay minutes US DOT attributed to each cause for IAH → SJU. Only delays of 15 minutes or more are attributed. What the five causes mean
Airlines on this route
Carriers with at least 200 flights, by the airline that operated each one.
| Carrier | Flights | On time | Cancelled | Median delay | Severe |
|---|---|---|---|---|---|
| United Airlines | 2,542 | 80.8% | 0.75% | -8 min | 5.9% |
| Spirit Airlines | 331 | 75.1% | 2.72% | -9 min | 11.8% |
United Airlines flew 88.5% of the 2,873 flights listed. Spirit Airlines cancelled 2.72% of its flights here against 0.75% for United Airlines.
United Airlines arrived on time 5.7 percentage points more often than Spirit Airlines on this route.
Flights on this route
Flight numbers with at least 600 operations here and still on the schedule.
Weekly and seasonal patterns
By day of week
Tuesday is historically the most reliable day and Saturday the least, a gap of 12.1 percentage points.
By month
- Jan: 83.8%
- Feb: 86.9%
- Mar: 83.1%
- Apr: 89.3%
- May: 82.5%
- Jun: 75.5%
- Jul: 66.6%
- Aug: 71.4%
- Sep: 87.8%
- Oct: 82.8%
- Nov: 81.4%
- Dec: 83.7%
July is historically the weakest month and April the strongest, a spread of 22.7 percentage points.
Reliability over time
July 2023 – July 2026
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 82.8% against 81.9% in the 12 months before — broadly unchanged.
Data and methodology
Calculated by FlyerIntel from 2,873 IAH → SJU flight records from the US DOT Bureau of Transportation Statistics, covering July 2023 – July 2026. Late means 15 or more minutes past scheduled arrival; cancelled and diverted flights are left out of on-time rates.
Full methodology · Data sources · Report a problem
Related research: How Long a Layover Needs to Be · Two Airlines on One Route · Best Time of Day to Fly From Major US Airports
Analysis last recomputed