Route profile
IAH→SJU
Flight reliability, delays and best times to fly from Houston to San Juan. · 2,007 miles
Right now
Current conditions at both ends of this route.
Aviation weather is not currently a factor.
Aviation weather is not currently a factor.
Airport conditions describe the airfield, not any individual flight. An airport operating normally is not a guarantee that a specific flight will depart on time.
Route reliability
July 2023 – June 2026
Better than 61% of comparable major US routes (4,577 compared)
Calculated from 2,780 flights. How this is calculated
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – June 2026
Best time to fly
On-time arrival rate by scheduled local departure time.
IAH → SJU flights departing 9 PM–5 AM arrived on time 85.1% of the time, against 57.4% for 6–9 PM departures — a gap of 27.7 percentage points.
By departure window
By departure hour
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – June 2026 · Buckets with fewer than 120 flights are not scored.
Why IAH → SJU runs late
Where US DOT attributed the delay minutes on this route.
crew, maintenance, boarding, fuelling — 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. A single late flight can carry more than one cause, and only delays of fifteen minutes or more are attributed at all.
A route inherits the problems of both ends and of the aircraft flying it. A large share attributed to late-arriving aircraft usually means the departure sits late in a busy rotation rather than that anything about this city pair is difficult, which is why the same route often performs very differently at different times of day.
Airlines on this route
Performance by the carrier that actually operated the flight.
| Carrier | Flights | On time | Cancelled | Median delay | Severe |
|---|---|---|---|---|---|
| United Airlines | 2,449 | 80.6% | 0.78% | -8 min | 6.1% |
| Spirit Airlines | 331 | 75.1% | 2.72% | -9 min | 11.8% |
United Airlines arrived on time 5.5 percentage points more often than Spirit Airlines on this route.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – June 2026 · Carriers with fewer than 200 flights on this route are not listed.
Individual flights on this route
The same route is not equally reliable at every hour. These are the flight numbers with enough operating history to judge separately.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – June 2026 · Flight numbers with fewer than 270 operations on this route, or no longer scheduled, are not listed.
Weekly and seasonal patterns
By day of week
Tuesday is historically the most reliable day and Saturday the least, a gap of 12.5 percentage points.
By month
July is historically the weakest month and April the strongest, a spread of 28.8 percentage points.
Historical trend
On-time arrival rate by month.
Over the most recent 12 months (2025-07 to 2026-06), on-time arrivals averaged 81.0% against 80.6% in the 12 months before — broadly unchanged.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – June 2026
Data and methodology
All figures on this page are calculated by FlyerIntel from 2,780 IAH → SJU flight records published by the US DOT Bureau of Transportation Statistics, covering July 2023 – June 2026. A flight is counted as delayed when it arrives 15 or more minutes after its scheduled arrival time, following BTS methodology. Cancelled and diverted flights have no arrival time and are excluded from on-time rates rather than counted as late.
Full methodology · Data sources · Report a problem
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