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DelayAtlas

Airport month record

SJUAPR

Luis Munoz Marin International in April 2026

Departures
3,190
Month
April 2026
National, same month
79.8%
Carriers
7
B+GRADE

Historical statistics for April 2026, not live status or a forecast for this year’s April. For today’s conditions at SJU, see live FAA status.

SJU in April lands a B+, about a point worse than the national rate of 79.8%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 3,190 flights, of which American Airlines flew 484 at 81.9% on time.

American Airlines is the most reliable of the three carriers covered here at 81.9% on time across 484 flights.

Key figures

On time

78.4%

Arrivals under 15 minutes late, of 3,156 completed departures

Avg delay

68 min

Across delayed arrivals only, not all flights

Cancelled

0.75%

Nationally in April: 0.90%

Whole year

77.8%

SJU across all twelve months

These figures cover 3,190 departures from Luis Munoz Marin International in April 2026. On time means an arrival less than 15 minutes after the scheduled gate time, the DOT's threshold, and the national comparison uses every US departure in the same month rather than the whole year.

Against the year

April next to SJU's other months

Against SJU's own year, April ran level with the twelve-month rate of 77.8%, which makes it number seven of twelve months, best first. Cancellations were unusually low for SJU in April, at 0.75% against 1.83% across the year. Either side of it, March ran 75.1% on time and May 84.7%, so this month sits in line with its neighbours.

SJU month by month
MonthFlightsOn timeAvg delayCancelledGrade
July 20253,41575.4%80 min1.55%B
August 20252,97570.9%80 min0.77%C+
September 20251,96580.7%69 min0.00%B+
October 20252,18679.1%68 min0.46%B+
November 20252,71581.8%87 min1.07%B
December 20253,39378.4%79 min1.77%B
January 20263,30673.3%91 min7.96%C−
February 20262,83574.7%79 min3.17%C−
March 20263,44175.1%73 min2.06%B
April 2026 (this page)3,19078.4%68 min0.75%B+
May 20262,87584.7%64 min0.21%B+
June 20263,09583.1%76 min0.61%B+

Departure window

The best time of day to leave SJU in April

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 18 points, against 11 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am772 flights89.2%
  • 8am–11am196 flights82.1%
  • 11am–2pm660 flights76.4%
  • 2pm–5pm735 flights71.6%
  • 5pm–8pm443 flights76.2%
  • 8pm–5am384 flights73.1%

Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 89.2% of the time, against 71.6% for the afternoon window. That is 18 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 772 flights scheduled in it.

Across the week, Friday is the strongest day at 84.0% on time and Monday the weakest at 73.6%. 10 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week73.6Mon80.2Tue78.6Wed77.3Thu84.0Fri80.5Sat74.4Sun
Monday: 73.6 percent on time. Tuesday: 80.2 percent on time. Wednesday: 78.6 percent on time. Thursday: 77.3 percent on time. Friday: 84.0 percent on time. Saturday: 80.5 percent on time. Sunday: 74.4 percent on time

Carrier by carrier

Which airlines ran best at SJU in April

The choice of carrier is not cosmetic here. American Airlines arrives on time 81.9% of the time; Frontier Airlines manages 71.1%. Sample sizes sit next to every figure, because a two-point gap across 434 flights means less than a ten-point one.

Carriers at SJU in April 2026
AirlineFlightsOn timeAvg delayCancelledGrade
JetBlue Airways1,02778.2%57 min0.19%B+
American Airlines48481.9%93 min0.21%B+
Frontier Airlines43471.1%101 min1.15%C
Spirit Airlinesthin sample32965.1%63 min4.26%C−
Delta Air Linesthin sample31887.7%54 min0.31%A+
United Airlinesthin sample30088.9%41 min0.33%A+
Southwest Airlinesthin sample29877.2%40 min0.00%B+

American leads Frontier by 11 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.

Route by route

Busiest routes out of SJU in April

Routes from SJU in April 2026
RouteFlightsOn timeAvg delayCancelledGrade
SJU to MCO · Orlando48079.2%87 min0.83%B+
SJU to JFK · New Yorkthin sample31084.1%53 min0.00%B+
SJU to MIA · Miamithin sample23873.9%93 min0.00%C+
SJU to PHL · Philadelphiathin sample22480.6%97 min3.12%B−
SJU to BOS · Bostonthin sample21569.8%46 min0.00%C+
SJU to ATL · Atlantathin sample20174.1%49 min0.00%C+
SJU to EWR · Newarkthin sample19181.0%81 min0.52%B+
SJU to FLL · Fort Lauderdalethin sample18069.5%53 min1.67%C
SJU to ORD · Chicagothin sample13885.5%98 min1.45%A
SJU to TPA · Tampathin sample12365.0%53 min2.44%C
SJU to BWI · Baltimorethin sample11168.2%59 min0.90%C+
SJU to CLT · Charlottethin sample10883.3%115 min0.00%B+
SJU to DFW · Dallas-Fort Worththin sample10779.8%55 min0.93%B+
SJU to BDL · Hartfordthin sample9071.1%52 min0.00%C+
SJU to IAD · Washingtonthin sample6293.5%66 min0.00%A+
SJU to IAH · Houstonthin sample6088.3%25 min0.00%A+
SJU to RDU · Raleighthin sample4087.5%51 min0.00%A+
SJU to DEN · Denverthin sample3090.0%41 min0.00%A+
SJU to HPN · White Plainsthin sample3082.8%73 min3.33%B−
SJU to STT · Charlotte Amaliethin sample3080.0%42 min0.00%B+
SJU to DCA · Washingtonthin sample3086.7%114 min0.00%A+
SJU to STX · Christianstedthin sample3080.0%43 min0.00%B+
SJU to DTW · Detroitthin sample3089.7%41 min0.00%A+

Delay causes

What held SJU up in April

One category carries most of the weight here. Late-arriving aircraft accounts for 48% of the 46,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.

  • Late-arriving aircraft
    48%
  • Carrier
    34%
  • National Airspace System
    18%
  • Extreme weather
    1%

48% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 46,000 reported delay minutes here, that single category outweighs weather by 48 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 46,305 reported delay minutes.

Cancellations are rare at 0.75%, below the national 0.90% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.

6.3% of arrivals land an hour or more late, close to the national 6.4%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, which a normal layover absorbs.

What to do with this

Flying from SJU in April

For a April trip through SJU: expect 78.4% on time and 0.75% cancelled, going by April 2026. The 5am–8am window was the strongest part of the day.

Related

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.