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DelayAtlas

Airport month record

SATMAY

San Antonio International in May 2026

Departures
3,485
Month
May 2026
National, same month
78.6%
Carriers
8
BGRADE

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

SAT in May lands a B, 2 points better than the national rate of 78.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 3,485 flights, of which Delta Air Lines flew 611 at 86.6% on time.

Delta Air Lines is the most reliable of the four carriers covered here at 86.6% on time across 611 flights.

Key figures

On time

80.7%

Arrivals under 15 minutes late, of 3,427 completed departures

Avg delay

79 min

Across delayed arrivals only, not all flights

Cancelled

1.38%

Nationally in May: 0.92%

Whole year

81.8%

SAT across all twelve months

These figures cover 3,485 departures from San Antonio 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 SAT's other months

Against SAT's own year, May ran about a point worse than the twelve-month rate of 81.8%, which makes it number nine of twelve months, best first. Either side of it, April ran 82.6% on time and June 73.5%, so a trip moved by a few weeks would have landed in a worse stretch.

SAT month by month
MonthFlightsOn timeAvg delayCancelledGrade
July 20253,69976.4%77 min1.49%B
August 20253,44481.5%79 min1.19%B
September 20253,33485.6%71 min0.63%A+
October 20253,65683.7%68 min0.38%B+
November 20253,44084.1%67 min1.19%B
December 20253,58883.7%66 min0.72%B+
January 20262,92184.8%96 min3.70%B−
February 20262,67186.3%67 min1.27%A
March 20263,43979.9%74 min1.37%B
April 20263,38482.6%66 min0.74%B+
May 2026 (this page)3,48580.7%79 min1.38%B
June 20263,39373.5%81 min1.65%C

Departure window

The best time of day to leave SAT in May

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 28 points, against 11 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am991 flights91.6%
  • 8am–11am418 flights87.9%
  • 11am–2pm682 flights81.1%
  • 2pm–5pm657 flights73.0%
  • 5pm–8pm598 flights69.3%
  • 8pm–5am139 flights63.5%

Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 63.5% on time, against 91.6% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 5am–8am window is the busiest, with 991 flights scheduled in it.

Across the week, Saturday is the strongest day at 85.9% on time and Friday the weakest at 77.2%. 9 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week78.7Mon79.7Tue81.6Wed79.2Thu77.2Fri85.9Sat83.0Sun
Monday: 78.7 percent on time. Tuesday: 79.7 percent on time. Wednesday: 81.6 percent on time. Thursday: 79.2 percent on time. Friday: 77.2 percent on time. Saturday: 85.9 percent on time. Sunday: 83.0 percent on time

Carrier by carrier

Which airlines ran best at SAT in May

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 86.6% of the time; Southwest Airlines manages 75.9%. Sample sizes sit next to every figure, because a two-point gap across 1,357 flights means less than a ten-point one.

Carriers at SAT in May 2026
AirlineFlightsOn timeAvg delayCancelledGrade
Southwest Airlines1,35775.9%53 min0.44%B+
American Airlines62882.5%142 min2.71%B
Delta Air Lines61186.6%74 min2.78%A
United Airlines46184.9%49 min0.43%B+
Envoy Airthin sample16678.4%83 min2.41%B
SkyWest Airlinesthin sample14883.6%280 min1.35%B
Frontier Airlinesthin sample6170.5%66 min0.00%C+
Alaska Airlinesthin sample5092.0%43 min0.00%A+

Delta leads Southwest 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 SAT in May

Routes from SAT in May 2026
RouteFlightsOn timeAvg delayCancelledGrade
SAT to DFW · Dallas-Fort Worth39078.0%168 min5.38%B−
SAT to DEN · Denverthin sample26678.8%44 min0.00%B+
SAT to ATL · Atlantathin sample25980.0%75 min4.63%B−
SAT to DAL · Dallasthin sample25282.4%65 min1.98%B
SAT to PHX · Phoenixthin sample23082.2%65 min0.00%B+
SAT to IAH · Houstonthin sample18479.3%51 min0.00%B+
SAT to ORD · Chicagothin sample17983.5%84 min1.12%B
SAT to LAS · Las Vegasthin sample17572.4%53 min0.57%C+
SAT to LAX · Los Angelesthin sample14980.8%103 min2.01%B
SAT to CLT · Charlottethin sample12186.8%104 min0.00%A+
SAT to HOU · Houstonthin sample10355.3%53 min0.00%D+
SAT to BNA · Nashvillethin sample8871.6%53 min0.00%C+
SAT to DTW · Detroitthin sample8790.6%52 min2.30%A
SAT to MSP · Minneapolisthin sample8790.8%66 min0.00%A+
SAT to SLC · Salt Lake Citythin sample8691.9%81 min0.00%A+
SAT to MCO · Orlandothin sample6374.6%74 min0.00%C+
SAT to ELP · El Pasothin sample6277.4%81 min0.00%B+
SAT to MDW · Chicagothin sample6279.0%44 min0.00%B+
SAT to SAN · San Diegothin sample5775.4%48 min0.00%B+
SAT to STL · St. Louisthin sample5689.1%62 min0.00%A+
SAT to EWR · Newarkthin sample5496.2%23 min1.85%A
SAT to MIA · Miamithin sample5475.9%71 min0.00%B+
SAT to BWI · Baltimorethin sample5284.6%40 min0.00%B+
SAT to SEA · Seattlethin sample5092.0%43 min0.00%A+
SAT to IAD · Washingtonthin sample5098.0%28 min0.00%A+

Delay causes

What held SAT up in May

Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 52,000 reported delay minutes.

  • Late-arriving aircraft
    35%
  • Carrier
    32%
  • Extreme weather
    17%
  • National Airspace System
    16%
  • Security
    0%

Extreme weather accounts for 17% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the comparison with the other months below is the more useful view of the risk. The national share is 6%, so this operation carries roughly 2.8 times the usual weather exposure. The split is drawn from 52,438 reported delay minutes.

Cancellations sit at 1.38% against a national 0.92%, which is ordinary. Diversions add another 0.29%.

6.1% of arrivals land an hour or more late, close to the national 7.1%. 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 a little over an hour, which a normal layover absorbs.

What to do with this

Flying from SAT in May

For a May trip through SAT: expect 80.7% on time and 1.38% cancelled, going by May 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.