US airport delays

What is disrupted right now, from the FAA's live status feed, and how often flights actually ran late, from the Department of Transportation's flight-by-flight records, which arrive about two to three months after the month ends. Back to World Pulse.

Live now — FAA · checked 20:15 UTC

BOS · Ground delay program
avg 148 min, max 399 min · runway construction
since 11-07 13:00 UTC (first seen)
LGA · Ground stop
· wind
since 11-07 19:30 UTC (first seen)
4 closure / restriction notices (mostly NOTAMs limiting some aircraft)
SNAClosure!SNA 11/003 SNA AD AP CLSD DLY 0730-1415 2611030730-2611081415
LASRestricted (NOTAM)!LAS 10/160 LAS AD AP CLSD TO NON SKED TRANSIENT GA ACFT EXC 24HR PPR 702-261-7775 2610281926-2701272300
LAXRestricted (NOTAM)!LAX 05/277 LAX AD AP CLSD TO NON SKED TRANSIENT GA ACFT EXC 24HR PPR CTC ATLANTIC AVIATION 310-258-9884 OR SIGNATURE AVIATION 310-410-9605 2605271826-2705281600
SANRestricted (NOTAM)!SAN 10/004 SAN AD AP CLSD TO NON SKED TRANSIENT GA ACFT EXC PPR 619-298-7704 2610011633-2701010800
Month Aug 2026 Jul 2026 Jun 2026 May 2026 Apr 2026 Mar 2026 Feb 2026 Jan 2026 Dec 2025 Nov 2025 Oct 2025 Sep 2025 Aug 2025 Measure Departures Arrivals
15%45%+ of departures 15+ min late dot size = flights · ring = FAA program live now

Nationally, January 2025

18.2%
of 523,435 departures ran 15+ min late · usual for January: 19.6% · 3.0% cancelled
Last 37 months · dashed = usual for that month (median of up to 5 earlier years, 2020 left out)
Where late-arrival minutes came from
Airline 36%
Late aircraft 35%
Air traffic 20%
Weather 9%
Security 0%

Airports, January 2025 (departures)

AirportCityFlightsLate 15+ vs usual CancelledAvg minMain cause
DFW Dallas/Fort Worth, TX 25,124 23.5% +5.7 6.3% 18 Late aircraft
DEN Denver, CO 24,732 23.4% -4.7 1.3% 15 Late aircraft
ATL Atlanta, GA 23,881 22.4% +6.5 5.2% 17 Airline
ORD Chicago, IL 21,643 19.7% -2.6 1.8% 15 Late aircraft
CLT Charlotte, NC 16,877 17.7% +3.2 4.5% 12 Late aircraft
PHX Phoenix, AZ 15,956 14.3% -1.1 0.9% 9 Airline
LAX Los Angeles, CA 15,157 13.9% -2.8 1.0% 10 Airline
LAS Las Vegas, NV 15,007 18.5% -0.6 1.1% 12 Late aircraft
MCO Orlando, FL 13,058 21.3% -0.9 1.6% 13 Late aircraft
SEA Seattle, WA 11,882 16.9% +0.6 0.9% 11 Airline
DCA Washington, DC 11,734 20.7% +2.0 9.3% 16 Late aircraft
LGA New York, NY 10,905 16.9% -4.1 3.0% 12 Late aircraft
SFO San Francisco, CA 10,839 13.9% -7.9 0.7% 11 Late aircraft
BOS Boston, MA 10,624 15.2% -5.8 2.4% 11 Air traffic
MIA Miami, FL 10,182 22.2% -0.5 2.1% 16 Airline
EWR Newark, NJ 10,144 17.3% -7.1 2.1% 12 Late aircraft
SLC Salt Lake City, UT 9,350 15.0% -0.7 0.8% 11 Airline
DTW Detroit, MI 9,253 21.0% +1.0 1.5% 16 Airline
IAH Houston, TX 9,250 22.3% +2.5 5.6% 18 Airline
MSP Minneapolis, MN 8,483 17.1% -1.3 1.1% 13 Airline
JFK New York, NY 8,327 17.1% -4.3 1.8% 13 Airline
FLL Fort Lauderdale, FL 7,892 24.7% +2.7 2.2% 16 Late aircraft
BNA Nashville, TN 7,404 17.1% -2.6 4.3% 12 Late aircraft
SAN San Diego, CA 7,189 16.9% +2.0 1.6% 13 Late aircraft
BWI Baltimore, MD 7,094 19.7% -3.0 4.4% 12 Airline
PHL Philadelphia, PA 6,688 17.6% +1.6 2.8% 16 Late aircraft
TPA Tampa, FL 6,454 19.5% +1.1 2.0% 14 Late aircraft
AUS Austin, TX 6,142 16.3% -1.0 2.4% 12 Late aircraft
DAL Dallas, TX 5,755 18.6% -2.5 5.1% 11 Late aircraft
MDW Chicago, IL 5,189 18.6% -8.0 2.0% 10 Airline
HNL Honolulu, HI 5,164 11.3% -6.9 1.8% 10 Airline
STL St. Louis, MO 4,717 17.5% -2.0 6.9% 13 Late aircraft
PDX Portland, OR 4,401 12.6% -1.3 0.9% 10 Airline
MSY New Orleans, LA 4,207 17.6% +2.7 10.0% 14 Late aircraft
RDU Raleigh/Durham, NC 4,205 14.9% -2.5 2.9% 14 Late aircraft
SMF Sacramento, CA 4,148 13.1% -2.1 0.9% 9 Late aircraft
HOU Houston, TX 4,122 16.9% -3.6 6.3% 10 Late aircraft
IAD Washington, DC 4,008 18.6% +3.2 3.1% 16 Airline
SJC San Jose, CA 3,697 10.5% -2.1 1.1% 7 Late aircraft
RSW Fort Myers, FL 3,562 18.0% -0.8 2.1% 13 Late aircraft
IND Indianapolis, IN 3,485 14.3% -2.2 4.0% 11 Air traffic
MCI Kansas City, MO 3,481 16.2% -0.1 8.4% 15 Airline
SNA Santa Ana, CA 3,478 15.8% +1.6 1.7% 15 Late aircraft
CMH Columbus, OH 3,283 15.2% -1.8 2.2% 12 Late aircraft
SJU San Juan, PR 3,208 25.8% +2.7 1.5% 21 Late aircraft
SAT San Antonio, TX 3,100 16.1% +4.0 3.6% 12 Late aircraft
PIT Pittsburgh, PA 3,071 14.6% -0.9 2.2% 11 Air traffic
PBI West Palm Beach/Palm Beach, FL 2,945 26.9% +3.0 1.9% 19 Late aircraft
CLE Cleveland, OH 2,924 17.3% -2.4 2.2% 15 Airline
OAK Oakland, CA 2,868 13.3% -3.3 0.9% 7 Airline
CVG Cincinnati, OH 2,405 16.0% -1.4 4.5% 15 Airline
BUR Burbank, CA 2,344 14.1% -0.6 2.8% 10 Late aircraft
JAX Jacksonville, FL 2,238 17.1% +1.2 4.2% 16 Airline
OGG Kahului, HI 2,237 10.4% -9.4 2.1% 11 Late aircraft
ONT Ontario, CA 1,941 14.7% +0.1 2.0% 12 Late aircraft
MKE Milwaukee, WI 1,929 15.5% -3.7 2.3% 13 Airline
OMA Omaha, NE 1,887 16.5% -0.9 1.9% 14 Airline
TUS Tucson, AZ 1,866 11.8% -3.5 1.7% 8 Airline
BOI Boise, ID 1,839 12.8% -1.9 0.5% 8 Airline
ABQ Albuquerque, NM 1,790 13.0% -3.0 1.5% 9 Late aircraft
BDL Hartford, CT 1,790 15.7% -1.4 3.1% 14 Airline
OKC Oklahoma City, OK 1,723 14.3% -0.5 3.3% 13 Airline
SDF Louisville, KY 1,701 16.5% -0.6 6.3% 20 Airline
RNO Reno, NV 1,673 14.9% +0.0 0.7% 11 Airline
CHS Charleston, SC 1,661 15.9% -0.6 9.7% 17 Late aircraft
MEM Memphis, TN 1,528 17.6% +0.5 4.3% 14 Airline
SRQ Sarasota/Bradenton, FL 1,499 18.7% -5.2 1.8% 18 Late aircraft
PSP Palm Springs, CA 1,446 11.4% -5.9 0.5% 10 Airline
ORF Norfolk, VA 1,441 15.5% -1.0 4.4% 18 Airline
BUF Buffalo, NY 1,396 18.7% -0.2 2.8% 15 Late aircraft
KOA Kona, HI 1,377 9.4% -8.4 1.6% 8 Late aircraft
SAV Savannah, GA 1,357 17.1% +0.5 10.7% 19 Late aircraft
LGB Long Beach, CA 1,345 10.8% -3.6 1.3% 8 Late aircraft
ELP El Paso, TX 1,337 13.2% -1.3 2.2% 10 Late aircraft
GRR Grand Rapids, MI 1,334 16.5% -4.3 1.6% 16 Airline
LIH Lihue, HI 1,319 10.3% -5.4 2.5% 10 Late aircraft
TUL Tulsa, OK 1,286 14.9% +3.7 3.5% 13 Late aircraft
GEG Spokane, WA 1,237 12.6% -4.1 0.2% 9 Airline
RIC Richmond, VA 1,200 15.7% -1.1 3.6% 14 Airline
BHM Birmingham, AL 1,195 17.0% -1.4 5.4% 15 Airline
ANC Anchorage, AK 1,187 15.5% +5.6 1.8% 11 Late aircraft
PVD Providence, RI 1,114 16.7% +0.1 3.5% 11 Late aircraft
GSP Greer, SC 1,098 15.0% +0.7 4.4% 11 Late aircraft
DSM Des Moines, IA 1,051 18.1% -2.3 2.3% 17 Late aircraft
ASE Aspen, CO 1,025 35.9% -0.3 5.3% 40 Air traffic
85 airports with 1,000+ flights this month, busiest first. Click a header to sort.

Airlines — arrivals 15+ min late

AirlineFlightsLateCanc.
Hawaiian6,69013.5%1.9%
Southwest105,30715.2%2.9%
Republic27,83316.0%4.0%
Alaska18,16317.6%1.3%
United62,00717.6%1.9%
Spirit17,54418.1%3.3%
Envoy21,89018.4%4.7%
American75,08819.2%3.7%
Delta76,30619.3%2.8%
SkyWest65,03620.9%2.1%
Allegiant9,34523.7%1.3%
JetBlue17,91824.5%1.8%
PSA21,09425.5%9.0%
Frontier15,52626.0%2.5%
Regional airlines (SkyWest, Envoy, Republic, PSA…) fly under the big brands' names.

Worst days this month

DateAirportLateCanc.
01-21IAH —100%
01-10ATL 93%84%
01-05STL 94%73%
01-06STL 92%62%
01-06DCA 72%88%
01-06BWI 90%58%
01-09DFW 70%86%
01-09DAL 62%75%
01-03SAN 86%11%
01-10DFW 72%30%
Ranked by share of flights late or cancelled; airports with 150+ flights that day.

FAA programs and delays, last 7 days

AirportWhatStarted (UTC)HoursPeak avgReason
LGAGround stop 11-07 19:30 0.8+ — wind
BOSGround stop 11-07 19:15 0.5 — runway construction
MCODeparture delays 11-07 18:15 2.0 31 min RWY:Maintenance
MIADeparture delays 11-07 18:00 0.5 16 min RWY:Construction
BOSDeparture delays 11-07 14:00 4.2 61 min RWY:Construction
BOSGround delay program 11-07 13:00 7.3+ 148 min runway construction
SEAGround delay program 11-07 01:30 4.0 51 min other
LGAGround stop 11-07 00:45 1.0 — airport volume
PHLDeparture delays 11-07 00:30 1.7 31 min TM Initiatives:SWAP:WX
SEADeparture delays 11-07 00:30 1.2 16 min RWY:Construction
JFKDeparture delays 11-07 00:15 1.8 16 min TM Initiatives:SWAP:WX
MCODeparture delays 11-07 00:15 0.3 16 min RWY:CLSD EQUIP OUTAGE
LASDeparture delays 11-06 23:45 2.3 16 min VOL:Volume
SANDeparture delays 11-06 23:15 1.5 31 min VOL:Compacted Demand
SEADeparture delays 11-06 21:30 0.5 16 min RWY:Construction
HPNGround stop 11-06 21:00 1.0 — thunderstorms
SANDeparture delays 11-06 20:30 2.2 16 min VOL:Compacted Demand
OPFDeparture delays 11-06 20:15 0.2 16 min VOL:Compacted Demand
EWRGround stop 11-06 19:00 2.0 — thunderstorms
BFIGround stop 11-06 19:00 0.7 — other
SANDeparture delays 11-06 19:00 0.2 16 min VOL:Volume
BFIGround delay program 11-06 18:30 6.5 258 min other
PHXDeparture delays 11-06 17:30 0.5 16 min VOL:Multi-taxi
EWRGround delay program 11-06 17:15 11.0 156 min thunderstorms
BOSGround stop 11-06 16:45 2.0 — thunderstorms
BOSDeparture delays 11-06 16:45 2.5 46 min WX:Thunderstorms
OPFDeparture delays 11-06 16:45 0.2 16 min TM Initiatives:MINIT:VOL
LGAGround stop 11-06 16:30 5.5 — thunderstorms
JFKGround stop 11-06 16:15 3.2 — thunderstorms
EWRGround stop 11-06 16:00 1.2 — thunderstorms
DCADeparture delays 11-06 16:00 5.5 136 min TM Initiatives:SWAP:WX
MIADeparture delays 11-06 16:00 0.5 31 min TM INITIATIVES:OTHER:CFR
ORDDeparture delays 11-06 15:45 0.5 16 min VOL:Multi-taxi
BOSGround delay program 11-06 15:30 8.5 144 min thunderstorms
SANGround delay program 11-06 15:00 12.7 26 min airport volume
SANDeparture delays 11-06 15:00 3.0 16 min VOL:Volume
DALDeparture delays 11-06 14:15 0.2 16 min VOL:Volume
BWIDeparture delays 11-06 14:00 6.5 136 min TM Initiatives:SWAP:WX
ORDDeparture delays 11-06 14:00 0.2 31 min VOL:Multi-taxi
PHLDeparture delays 11-06 14:00 7.7 241 min TM Initiatives:SWAP:WX
EWRGround stop 11-06 13:45 1.5 — thunderstorms
OPFDeparture delays 11-06 13:45 0.2 16 min VOL:Compacted Demand
LGAGround delay program 11-06 13:15 12.5 174 min thunderstorms
TEBDeparture delays 11-06 13:00 12.2 361 min TM Initiatives:SWAP:WX
DCADeparture delays 11-06 12:45 0.8 61 min WX:Thunderstorms
EWRDeparture delays 11-06 12:45 10.0 211 min TM Initiatives:SWAP:WX
JFKDeparture delays 11-06 12:30 10.0 136 min TM Initiatives:SWAP:WX
LGAGround stop 11-06 12:00 1.2 — thunderstorms
LGADeparture delays 11-06 11:45 12.5 166 min TM Initiatives:SWAP:WX
TEBDeparture delays 11-06 11:45 0.7 31 min TM Initiatives:SWAP:WX
JFKGround stop 11-06 11:15 4.8 — thunderstorms
BOSGround stop 11-05 23:30 0.8 — airspace volume
BFIGround delay program 11-05 22:15 6.8 161 min other
BFIGround stop 11-05 21:30 0.8 — other
SANDeparture delays 11-05 21:15 0.8 16 min VOL:Compacted Demand
BFIDeparture delays 11-05 21:00 3.0 16 min OTHER: TEMP TOWER OPS
SANDeparture delays 11-05 20:00 0.2 16 min VOL:Compacted Demand
HOUGround stop 11-05 19:45 0.2 — aircraft emergency
BFIGround stop 11-05 19:30 0.5 — other
DALDeparture delays 11-05 19:15 0.2 16 min VOL:Volume
OPFDeparture delays 11-05 18:45 0.5 16 min VOL:Compacted Demand
SEADeparture delays 11-05 17:15 0.2 16 min RWY:Construction
BFIGround stop 11-05 16:30 1.0 — airport volume
EWRDeparture delays 11-05 14:30 1.5 31 min TM Initiatives:MINIT:VOL
SANGround delay program 11-05 14:15 13.5 38 min airport volume
LGADeparture delays 11-05 14:15 1.8 16 min TM Initiatives:MINIT:WX
PHLDeparture delays 11-05 14:15 1.8 16 min TM Initiatives:MIT:VOL
TEBDeparture delays 11-05 14:15 7.5 76 min TM Initiatives:Metering:VOL
MIADeparture delays 11-05 02:15 0.2 16 min VOL:Multi-taxi
SANDeparture delays 11-05 01:45 3.0 31 min VOL:Compacted Demand
ATLGround stop 11-04 22:45 0.7 — thunderstorms
DALDeparture delays 11-04 22:45 2.5 16 min VOL:Volume
LGADeparture delays 11-04 22:15 0.7 31 min TM Initiatives:MINIT:VOL
SANDeparture delays 11-04 21:45 2.3 16 min VOL:Volume
OPFDeparture delays 11-04 19:30 0.2 16 min WX:Thunderstorms
MIADeparture delays 11-04 18:45 0.3 15 min WX:Thunderstorms
MIADeparture delays 11-04 16:15 2.2 46 min WX:Thunderstorms
ATLGround stop 11-04 16:00 2.0 — thunderstorms
ATLDeparture delays 11-04 16:00 2.5 46 min WX:Thunderstorms
SANGround delay program 11-04 14:45 6.5 37 min airport volume
FLLDeparture delays 11-04 02:15 10.0 46 min TM Initiatives:MIT:WX
MIADeparture delays 11-04 01:30 10.7 31 min TM Initiatives:MIT:WX
FLLDeparture delays 11-04 00:45 1.0 46 min TM Initiatives:MIT:WX
TEBDeparture delays 11-03 21:30 2.8 31 min STAFF:Staffing
SFODeparture delays 11-03 19:30 2.8 16 min WX:Wind
IAHDeparture delays 11-03 18:45 8.8 76 min WX:Thunderstorms
HOUGround stop 11-03 18:30 1.0 — thunderstorms
IAHGround stop 11-03 18:30 1.0 — thunderstorms
SANDeparture delays 11-03 18:00 0.2 16 min VOL:Compacted Demand
EWRDeparture delays 11-03 17:30 0.2 31 min STAFF:Staffing
PHXDeparture delays 11-03 17:30 0.5 16 min VOL:Multi-taxi
MIADeparture delays 11-03 17:00 2.2 16 min RWY:Construction
SFOGround stop 11-03 16:45 0.7 — wind
IAHDeparture delays 11-03 16:45 1.0 31 min WX:Thunderstorms
MCODeparture delays 11-03 16:45 0.5 16 min TM Initiatives:MIT:WX
TEBDeparture delays 11-03 15:30 2.5 46 min STAFF:Staffing
EWRDeparture delays 11-03 15:00 2.2 16 min STAFF:Staffing
SFOGround delay program 11-03 14:15 14.5 114 min wind
MIADeparture delays 11-03 14:00 0.7 16 min WX:Thunderstorms
DALDeparture delays 11-03 03:30 5.0 46 min WX:Thunderstorms
SANDeparture delays 11-03 03:30 1.5 16 min VOL:Compacted Demand
FLLGround stop 11-03 02:30 1.2 — thunderstorms
MIAGround delay program 11-03 00:00 4.0 146 min thunderstorms
MIADeparture delays 11-03 00:00 3.2 91 min TM Initiatives:MIT:WX
SANDeparture delays 11-02 22:30 4.8 16 min VOL:Compacted Demand
LGAGround stop 11-02 21:30 0.7 — airspace volume
ORDDeparture delays 11-02 21:15 1.8 15 min WX:Low Ceilings
FLLGround stop 11-02 21:00 3.2 — thunderstorms
ASEArrival delays 11-02 21:00 3.2 16 min ASE / WX:Low Ceilings
DJTDeparture delays 11-02 21:00 3.2 61 min WX:Thunderstorms
MIAGround stop 11-02 20:30 3.5 — thunderstorms
PHXDeparture delays 11-02 19:00 0.2 16 min VOL:Multi-taxi
DJTGround stop 11-02 18:45 1.8 — thunderstorms
FLLGround delay program 11-02 18:45 9.8 133 min thunderstorms
MIAGround stop 11-02 18:30 1.5 — thunderstorms
ORDDeparture delays 11-02 18:30 0.2 16 min WX:Low Ceilings
FLLGround stop 11-02 18:00 0.8 — thunderstorms
FMYDeparture delays 11-02 18:00 6.3 61 min WX:Thunderstorms
PHXDeparture delays 11-02 17:30 0.5 16 min VOL:Multi-taxi
SEADeparture delays 11-02 16:15 3.5 31 min WX:Fog
APFDeparture delays 11-02 16:00 8.2 121 min WX:Thunderstorms
MIAGround stop 11-02 14:15 2.5 — thunderstorms
FLLGround stop 11-02 14:15 2.8 — thunderstorms
DJTGround stop 11-02 14:15 2.8 — thunderstorms
SANGround delay program 11-02 13:45 12.0 29 min airport volume
TEBDeparture delays 11-02 13:45 4.2 46 min OTHER: INDIVIDUAL RELEASE
OPFDeparture delays 11-02 13:30 9.7 16 min TM Initiatives:MINIT:WX
RSWDeparture delays 11-02 13:15 11.0 91 min WX:Thunderstorms
FLLDeparture delays 11-02 13:00 14.3 166 min TM Initiatives:MIT:WX
MIADeparture delays 11-02 13:00 6.8 106 min TM Initiatives:MIT:WX
SFOGround delay program 11-02 03:00 1.2 62 min other
SFOGround stop 11-02 02:30 0.5 — STAFFING
MCODeparture delays 11-02 02:15 3.0 31 min WX:Thunderstorms
MCODeparture delays 11-02 00:30 1.5 31 min TM Initiatives:MIT:WX
LASDeparture delays 11-01 23:30 0.5 16 min WX:Thunderstorms
DCADeparture delays 11-01 23:15 0.5 16 min TM Initiatives:ESP:VOL
LASGround delay program 11-01 23:00 2.7 49 min wind
DJTGround stop 11-01 21:45 2.3 — thunderstorms
LASGround stop 11-01 21:30 1.5 — wind
YEGGround stop 11-01 21:30 7.5 — fog
SANDeparture delays 11-01 21:15 1.8 16 min VOL:Compacted Demand
DJTDeparture delays 11-01 20:30 5.5 76 min WX:Thunderstorms
MCODeparture delays 11-01 20:30 3.7 31 min TM Initiatives:MIT:WX
MIADeparture delays 11-01 19:45 9.5 76 min TM Initiatives:MIT:WX
PHXDeparture delays 11-01 19:30 3.5 31 min RWY:Rwy Change - Operational Necessity
PHXGround stop 11-01 19:15 1.3 — wind
RSWDeparture delays 11-01 18:15 6.0 16 min WX:Thunderstorms
ORDDeparture delays 11-01 17:30 1.0 16 min VOL:Volume
PHXDeparture delays 11-01 17:30 1.2 16 min WX:Low Ceilings
YEGGround stop 11-01 17:15 2.0 — fog
PHXGround stop 11-01 17:00 0.7 — low ceilings
LASDeparture delays 11-01 17:00 6.2 16 min WX:Thunderstorms
FLLGround delay program 11-01 16:45 6.5 56 min thunderstorms
LASDeparture delays 11-01 16:00 0.2 16 min WX:Wind
FLLGround stop 11-01 15:30 1.2 — THUNDERSTORMS
PHLDeparture delays 11-01 15:00 0.5 31 min TM Initiatives:MIT:STAFFING
FLLDeparture delays 11-01 13:45 15.5 151 min TM Initiatives:MIT:WX
MIADeparture delays 11-01 13:45 4.5 31 min TM Initiatives:MIT:WX
DFWDeparture delays 11-01 13:30 7.3 61 min WX:Low Visibility
DFWGround stop 11-01 13:00 1.0 — LOW
LASDeparture delays 10-31 21:15 0.2 16 min VOL:Compacted Demand

Most disrupted, last 30 days (FAA)

AirportGSGDPDelayHours
SAN41827232
LAS10926115
LGA9223106
BOS7713100
MIA313897
TEB312591
SFO510783
FLL521073
EWR741069
YUL011060
PHX442548
AUS37043
DCA51739
PHL111033
SEA212331
Recording since 2026-10-14. The FAA keeps no public history, so this is only what we have polled (every 15 minutes).
Sources. Delay rates: US DOT Bureau of Transportation Statistics, Reporting Carrier On-Time Performance (public domain). It covers domestic flights on airlines with at least 0.5% of US domestic passenger revenue, about 600,000 flights a month; smaller carriers and international flights are not in it. Live status: FAA Air Traffic Control System Command Center, NAS Status (public domain). Airport locations: OurAirports (public domain).
Definitions. Late means 15+ minutes after schedule, out of flights that operated. Causes are reported by airlines for arrivals 15+ minutes late. "Late aircraft" is the knock-on from an earlier delay to the same plane, so it says nothing about where the trouble started. "Air traffic" (the NAS category) covers airport capacity, traffic volume and non-extreme weather. "Usual" is the median of the same month in up to five earlier years, with 2020 left out; it appears once two earlier years exist.