Airport month record

SJUMAY

Luis Munoz Marin International in May 2026

Departures: 2,875
Month: May 2026
National, same month: 78.6%
Carriers: 6

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

SJU in May earns a B+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 6 points better than the national rate of 78.6%. When something does go wrong the average delay runs about an hour. That rests on 2,875 flights, of which JetBlue Airways flew 1,007 at 85.5% on time.

JetBlue Airways is the most reliable of the three carriers covered here at 85.5% on time across 1,007 flights.

On time

84.7%

Arrivals under 15 minutes late, of 2,857 completed departures

Avg delay

64 min

Across delayed arrivals only, not all flights

Cancelled

0.21%

Nationally in May: 0.92%

Whole year

77.8%

SJU across all twelve months

These figures cover 2,875 departures from Luis Munoz Marin International in May 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

May next to SJU's other months

Against SJU's own year, May ran 7 points better than the twelve-month rate of 77.8%, which makes it the best of the twelve months in the data. Cancellations were unusually low for SJU in May, at 0.21% against 1.83% across the year. Either side of it, April ran 78.4% on time and June 83.1%, so a trip moved by a few weeks would have landed in a worse stretch.

SJU month by month
Month	Flights	On time	Avg delay	Cancelled	Grade
July 2025	3,415	75.4%	80 min	1.55%	B
August 2025	2,975	70.9%	80 min	0.77%	C+
September 2025	1,965	80.7%	69 min	0.00%	B+
October 2025	2,186	79.1%	68 min	0.46%	B+
November 2025	2,715	81.8%	87 min	1.07%	B
December 2025	3,393	78.4%	79 min	1.77%	B
January 2026	3,306	73.3%	91 min	7.96%	C−
February 2026	2,835	74.7%	79 min	3.17%	C−
March 2026	3,441	75.1%	73 min	2.06%	B
April 2026	3,190	78.4%	68 min	0.75%	B+
May 2026 (this page)	2,875	84.7%	64 min	0.21%	B+
June 2026	3,095	83.1%	76 min	0.61%	B+

Departure window

The best time of day to leave SJU in May

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 17 points, against 3 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am718 flights94.2%
8am–11am201 flights91.0%
11am–2pm496 flights83.3%
2pm–5pm708 flights77.4%
5pm–8pm508 flights80.2%
8pm–5am244 flights84.4%

Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 94.2% of the time, against 77.4% for the afternoon window. That is 17 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 718 flights scheduled in it.

Across the week, Friday is the strongest day at 87.6% on time and Sunday the weakest at 81.8%. 6 points is a smaller lever than departure hour, but it is free.

Carrier by carrier

Which airlines ran best at SJU in May

The three carriers here are closely matched: 3 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.

Carriers at SJU in May 2026
Airline	Flights	On time	Avg delay	Cancelled	Grade
JetBlue Airways	1,007	85.5%	51 min	0.00%	A+
Frontier Airlines	457	83.7%	79 min	0.00%	B+
American Airlines	452	83.0%	107 min	0.44%	B+
United Airlinesthin sample	320	87.7%	59 min	0.31%	A+
Southwest Airlinesthin sample	316	76.3%	45 min	0.00%	B+
Delta Air Linesthin sample	314	91.6%	31 min	0.64%	A+

No carrier stands out. JetBlue tops the table at 85.5%, 3 points clear of the bottom, which is inside the range this kind of sample moves year to year.

Route by route

Busiest routes out of SJU in May

Routes from SJU in May 2026
Route	Flights	On time	Avg delay	Cancelled	Grade
SJU to MCO · Orlando	475	85.9%	65 min	0.21%	A+
SJU to JFK · New Yorkthin sample	254	88.5%	41 min	0.39%	A+
SJU to MIA · Miamithin sample	216	79.6%	112 min	0.00%	B+
SJU to PHL · Philadelphiathin sample	197	85.6%	100 min	0.51%	A+
SJU to ATL · Atlantathin sample	185	87.4%	36 min	0.54%	A+
SJU to FLL · Fort Lauderdalethin sample	174	79.7%	43 min	0.00%	B+
SJU to BOS · Bostonthin sample	145	82.1%	55 min	0.00%	B+
SJU to EWR · Newarkthin sample	135	85.8%	91 min	0.74%	A+
SJU to TPA · Tampathin sample	116	71.6%	52 min	0.00%	C+
SJU to ORD · Chicagothin sample	105	83.3%	55 min	0.00%	B+
SJU to CLT · Charlottethin sample	95	84.0%	123 min	1.05%	B
SJU to BDL · Hartfordthin sample	93	88.0%	31 min	0.00%	A+
SJU to BWI · Baltimorethin sample	90	79.8%	49 min	0.00%	B+
SJU to DFW · Dallas-Fort Worththin sample	89	82.0%	29 min	0.00%	B+
SJU to IAH · Houstonthin sample	72	91.7%	23 min	0.00%	A+
SJU to IAD · Washingtonthin sample	62	87.1%	36 min	0.00%	A+
SJU to JAX · Jacksonvillethin sample	52	92.3%	40 min	0.00%	A+
SJU to RDU · Raleighthin sample	39	92.3%	34 min	0.00%	A+
SJU to DCA · Washingtonthin sample	31	80.6%	51 min	0.00%	B+
SJU to STX · Christianstedthin sample	31	87.1%	39 min	0.00%	A+
SJU to STT · Charlotte Amaliethin sample	31	93.5%	45 min	0.00%	A+
SJU to DEN · Denverthin sample	31	93.5%	16 min	0.00%	A+
SJU to DTW · Detroitthin sample	31	93.5%	62 min	0.00%	A+

Delay causes

What held SJU up in May

One category carries most of the weight here. Late-arriving aircraft accounts for 46% of the 28,000 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
46%
Carrier
40%
National Airspace System
13%
Extreme weather
0%
Security
0%

46% 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 28,000 reported delay minutes here, that single category outweighs weather by 46 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 27,993 reported delay minutes.

Cancellations are rare at 0.21%, below the national 0.92% 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.

Badly late arrivals are rare here: only 3.7% land an hour or more behind schedule, against 7.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.

What to do with this

Flying from SJU in May

For a May trip through SJU: this is one of the better months to be flying from here, 84.7% on time with 0.21% cancelled. That is a base rate for the month as a whole; a single storm can still spoil a particular day.

Luis Munoz Marin International (SJU), the whole year
SJU in July75.4%
SJU in August70.9%
SJU in September80.7%
SJU in October79.1%
SJU in November81.8%
SJU in December78.4%
SJU in January73.3%
SJU in February74.7%
SJU in March75.1%
SJU in April78.4%
SJU in June83.1%

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.

Key figures