Weather and Delay Correlation Engine

Disruption watchlist

Measured sensitivity meets the forecast

Airports with a proven low-visibility penalty and IFR/LIFR in their current forecast for the next 36 hours. As of 18:06 UTC.

Airport	Forecast	Window	Historical impact in these conditions
BKK Bangkok	Low (IFR)	Fri 15:00 → Fri 19:00 local	arrivals late 25% → 65%
BNE Brisbane	Low (IFR)	Fri 04:06 → Fri 09:00 local	arrivals late 17% → 47%
ORD Chicago	Low (IFR)	Thu 14:00 → Thu 20:00 local	arrivals late 25% → 46% · 4.5× cancellations
PHL Philadelphia	Low (IFR)	Fri 04:00 → Fri 07:00 local	arrivals late 25% → 43% · 2.3× cancellations
LGA New York	Low (IFR)	Fri 05:00 → Fri 11:00 local	arrivals late 22% → 39% · 1.4× cancellations
DMK Bangkok	Low (IFR)	Fri 15:00 → Fri 19:00 local	arrivals late 15% → 31%
HPN White Plains	Low (IFR)	Fri 05:00 → Fri 08:00 local	arrivals late 33% → 48% · 1.7× cancellations
DUR Durban	Low (IFR)	Thu 20:06 → Thu 21:00 local	arrivals late 27% → 41%
HAN Hanoi	Low (IFR)	Fri 03:00 → Fri 05:00 local	arrivals late 21% → 35% · 4.0× cancellations
CTS Sapporo	Low (IFR)	Fri 06:00 → Fri 08:00 local	arrivals late 12% → 25% · 1.9× cancellations
MDW Chicago	Low (IFR)	Thu 14:00 → Thu 20:00 local	arrivals late 23% → 36% · 5.8× cancellations
OOL Gold Coast	Low (IFR)	Fri 04:06 → Fri 13:00 local	arrivals late 22% → 35%

Where ceilings hurt

Where low ceilings actually hurt

Arrival delay and cancellation rates by flight-rules category, per airport. Cards show airports with a statistically supported low-visibility penalty.

CAN Guangzhou

Clear air vs low visibility: arrivals late 13% → 64% · cancellations 12.2×

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	13%	-7.3m	0.9%	51,978
Marginal (MVFR)	24%	+7.8m	2.4%	5,491
Low (IFR)	66%	+38.9m	12%	142
Very low (LIFR)	36%	+0.7m	0.0%	11

BCN Barcelona

Clear air vs low visibility: arrivals late 26% → 67% · cancellations 7.1×

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	26%	+10.5m	1.7%	95,220
Marginal (MVFR)	38%	+31.0m	4.2%	5,010
Low (IFR)	67%	+70.9m	12%	278
Very low (LIFR)	—	—	—	0

BKK Bangkok

Clear air vs low visibility: arrivals late 25% → 65%

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	25%	+8.4m	16%	34,938
Marginal (MVFR)	40%	+21.0m	17%	1,701
Low (IFR)	63%	+35.1m	18%	277
Very low (LIFR)	77%	+44.8m	16%	47

MEL Melbourne

Clear air vs low visibility: arrivals late 25% → 58% · cancellations 5.0×

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	25%	+8.3m	1.1%	18,518
Marginal (MVFR)	40%	+18.7m	3.0%	2,269
Low (IFR)	57%	+37.9m	5.8%	524
Very low (LIFR)	63%	+45.6m	3.9%	123

FLL Fort Lauderdale

Clear air vs low visibility: arrivals late 22% → 54%

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	22%	+6.9m	2.2%	14,852
Marginal (MVFR)	30%	+18.9m	3.6%	694
Low (IFR)	42%	+17.1m	1.3%	73
Very low (LIFR)	76%	+104.3m	2.6%	37

IAH Houston

Clear air vs low visibility: arrivals late 14% → 45%

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	14%	-0.5m	0.9%	33,537
Marginal (MVFR)	17%	+3.8m	0.8%	833
Low (IFR)	45%	+21.1m	0.0%	76
Very low (LIFR)	—	—	—	0

BNE Brisbane

Clear air vs low visibility: arrivals late 17% → 47%

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	17%	+3.4m	4.0%	19,289
Marginal (MVFR)	17%	+4.0m	4.7%	562
Low (IFR)	23%	+6.8m	4.7%	61
Very low (LIFR)	75%	+64.5m	1.8%	52

AYT Antalya

Clear air vs low visibility: arrivals late 21% → 49% · cancellations 12.9×

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	21%	+9.3m	0.3%	28,622
Marginal (MVFR)	25%	+15.8m	0.8%	1,989
Low (IFR)	49%	+48.2m	4.3%	87
Very low (LIFR)	—	—	—	0

MNL Manila

Clear air vs low visibility: arrivals late 15% → 41%

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	15%	-2.7m	0.1%	16,525
Marginal (MVFR)	23%	+5.1m	0.2%	4,337
Low (IFR)	39%	+22.2m	0.0%	243
Very low (LIFR)	62%	+34.1m	0.0%	26

DFW Dallas-Fort Worth

Clear air vs low visibility: arrivals late 19% → 40%

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	19%	+4.2m	0.0%	59,355
Marginal (MVFR)	18%	+7.1m	0.0%	2,562
Low (IFR)	50%	+70.3m	0.0%	761
Very low (LIFR)	19%	+8.4m	0.0%	345

BIL Billings

Clear air vs low visibility: arrivals late 26% → 48% · cancellations 1.2×

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	26%	+25.7m	4.7%	2,105
Marginal (MVFR)	38%	+45.8m	3.5%	118
Low (IFR)	44%	+49.9m	5.7%	27
Very low (LIFR)	53%	+140.4m	6.3%	15

ORD Chicago

Clear air vs low visibility: arrivals late 25% → 46% · cancellations 4.5×

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	25%	+11.8m	0.8%	73,313
Marginal (MVFR)	33%	+19.7m	0.9%	9,825
Low (IFR)	49%	+52.2m	3.9%	3,957
Very low (LIFR)	29%	+27.5m	0.9%	720

ALC Alicante

Clear air vs low visibility: arrivals late 25% → 45% · cancellations 18.8×

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	25%	+9.4m	0.8%	18,980
Marginal (MVFR)	25%	+7.7m	0.0%	507
Low (IFR)	—	—	—	0
Very low (LIFR)	45%	+25.0m	14%	42

PHL Philadelphia

Clear air vs low visibility: arrivals late 25% → 43% · cancellations 2.3×

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	25%	+11.3m	0.1%	23,205
Marginal (MVFR)	31%	+20.9m	0.1%	2,605
Low (IFR)	42%	+32.2m	0.3%	759
Very low (LIFR)	80%	+54.6m	0.0%	20

SZX Shenzhen

Clear air vs low visibility: arrivals late 18% → 36% · cancellations 3.7×

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	18%	+0.5m	0.7%	40,251
Marginal (MVFR)	27%	+11.3m	1.2%	3,740
Low (IFR)	36%	+17.4m	3.0%	400
Very low (LIFR)	38%	+52.0m	0.0%	81

NAP Napoli

Clear air vs low visibility: arrivals late 28% → 46%

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	28%	+10.4m	0.6%	10,795
Marginal (MVFR)	31%	+10.8m	0.7%	398
Low (IFR)	45%	+19.9m	0.0%	20
Very low (LIFR)	46%	+29.5m	0.0%	37

Inherited delay

Was it the weather back there?

Arrival delay at a clear destination, attributed to the weather at the origin when the flight was scheduled out. 2,258,359 origin↔destination pairs matched. Each origin is compared with its own clear-weather baseline.

Across 234 origins with enough history, the median within-origin effect of low ceilings at departure is +1.3 percentage points of late arrivals at a clear destination (an effect at only 135 of 234). Most airports absorb it. Cancellations are the robust part: with the destination clear, cancellation risk rises from 0.9% when the origin is clear to 1.8% when the origin is LIFR. The heavy exporters:

Origins that export the most delay when their ceilings drop

VLC Valencia 21% → 83% of arrivals from here run late once its ceilings drop (24 low-vis departures)
BCN Barcelona 26% → 76% of arrivals from here run late once its ceilings drop (229 low-vis departures)
BKK Bangkok 21% → 70% of arrivals from here run late once its ceilings drop (82 low-vis departures)
BNE Brisbane 19% → 63% of arrivals from here run late once its ceilings drop (27 low-vis departures)
NCE Nice 36% → 80% of arrivals from here run late once its ceilings drop (25 low-vis departures)
CAN Guangzhou 23% → 67% of arrivals from here run late once its ceilings drop (43 low-vis departures)
BRC San Carlos de Bariloche 24% → 68% of arrivals from here run late once its ceilings drop (90 low-vis departures)
MEL Melbourne 19% → 58% of arrivals from here run late once its ceilings drop (320 low-vis departures)

Who cancels first

Same weather, different playbooks

Cancellation and delay rates in clear (VFR) vs low-visibility (IFR+LIFR) conditions, for airline-hub pairs with enough history.

Airline	Hub	Cancelled: clear → low-vis	Delayed >15m: clear → low-vis	Low-vis flights
BC (BC)	OKA Naha	0.7% → 70%	27% → 33%	40
JL (JL)	OKA Naha	1.4% → 69%	42% → 59%	55
MM (MM)	OKA Naha	1.2% → 68%	11% → 7.7%	40
NU (NU)	OKA Naha	1.0% → 66%	16% → 38%	70
6J (6J)	OKA Naha	0.4% → 63%	9.8% → 0.0%	30
NH (NH)	OKA Naha	1.9% → 64%	18% → 10%	140
RC (RC)	OKA Naha	6.8% → 59%	14% → 27%	27
UO (UO)	HND Tokyo	1.4% → 23%	19% → 26%	26
Cape Air (9K)	BOS Boston	4.7% → 24%	32% → 52%	306
Aeroflot Russian Airlines (SU)	IST Istanbul	4.1% → 23%	36% → 40%	26
Eurowings (EW)	LHR London	0.7% → 18%	18% → 26%	28
WestJet (WS)	YYZ Toronto	2.4% → 19%	14% → 24%	84
CPA (CPA)	HKG Hong Kong	1.3% → 18%	21% → 24%	125
JETSMART AIRLINES (WJ)	BRC San Carlos de Bariloche	2.2% → 18%	23% → 32%	34

Board honesty

When the board says 30 minutes, believe more

Every board update is stored, not just the final state, so the first delay a board admits can be compared with how the flight actually ran. Grouped by that first posted delay. Read it like this: a 16:00 departure whose board first shows a 27-minute delay (16:27) actually pushes back around 16:47 on average. Tracking since 2026-07-17. See cancellation risk after each push →

Departures

Delay first posted	Actual delay (avg)	Grew by	Got ≥10 min worse	Flights
10–20 min (avg 13m)	+27.8m	+14.5m	40%	245,212
20–40 min (avg 27m)	+47.4m	+20.5m	50%	213,244
40–70 min (avg 51m)	+78.0m	+27.0m	58%	112,110
70+ min (avg 130m)	+150.2m	+20.3m	57%	86,876

Arrivals

Delay first posted	Actual delay (avg)	Grew by	Got ≥10 min worse	Flights
10–20 min (avg 14m)	+17.3m	+3.7m	20%	253,398
20–40 min (avg 28m)	+33.7m	+6.2m	24%	222,348
40–70 min (avg 52m)	+60.8m	+9.2m	28%	128,271
70+ min (avg 134m)	+138.8m	+4.5m	31%	114,544

Most optimistic first estimates (departures)

Bahamasair +82 min beyond the first posted delay, on average · 91% get ≥10 min worse · 95 delayed departures
Tus +65 min beyond the first posted delay, on average · 89% get ≥10 min worse · 217 delayed departures
Blue Bird Airways +55 min beyond the first posted delay, on average · 76% get ≥10 min worse · 177 delayed departures
AZIMUTH AIRLINES +53 min beyond the first posted delay, on average · 60% get ≥10 min worse · 260 delayed departures
Contour Aviation +51 min beyond the first posted delay, on average · 65% get ≥10 min worse · 388 delayed departures
Arkia Israeli +47 min beyond the first posted delay, on average · 82% get ≥10 min worse · 768 delayed departures

The hangover

Delays outlast the weather

Arrivals landing in clear conditions, grouped by what the weather did in the hours before. Backlogs take time to clear, and some hubs clear much slower than others.

Conditions leading up to arrival	% delayed >15m	Avg delay	Flights
Clear now, IFR/LIFR within past 3 h	23%	+8.8m	32,384
Clear now, IFR/LIFR 3–6 h ago	23%	+8.6m	53,716
Clear for 6+ h	21%	+5.2m	2,390,238

Slowest to recover

PEK Beijing 14% → 46% of arrivals late in the 3 h after weather clears, vs steady clear air (665 arrivals)
ITM Osaka 16% → 44% of arrivals late in the 3 h after weather clears, vs steady clear air (112 arrivals)
DCA Washington 23% → 46% of arrivals late in the 3 h after weather clears, vs steady clear air (265 arrivals)
SDF Louisville 24% → 43% of arrivals late in the 3 h after weather clears, vs steady clear air (35 arrivals)
SZX Shenzhen 18% → 37% of arrivals late in the 3 h after weather clears, vs steady clear air (597 arrivals)
SYD Sydney 19% → 38% of arrivals late in the 3 h after weather clears, vs steady clear air (193 arrivals)

Raw ceiling & wind

Raw ceiling and wind, not just categories

Arrivals matched to the raw METAR values in force. Pooled across airports for now; per-hub curves arrive as data grows. Raw fields tracked since 2026-06-30, 4,042,096 arrivals so far.

By cloud-ceiling height

Band	% delayed >15m	Avg delay	Cancelled	Flights
<200 ft	24%	+11.8m	2.0%	2,032
200–500 ft	24%	+10.0m	2.2%	19,463
500–1,000 ft	24%	+8.9m	1.9%	81,936
1,000–2,500 ft	23%	+7.7m	1.5%	219,206
≥2,500 ft / none	21%	+5.3m	1.5%	3,719,459

By wind / gust speed

Band	% delayed >15m	Avg delay	Cancelled	Flights
<15 kt	21%	+5.0m	1.5%	3,606,914
15–24 kt	25%	+8.8m	1.4%	370,931
25–34 kt	31%	+14.8m	2.3%	58,189
≥35 kt	41%	+32.4m	10%	6,062

Weather barely moves arrivals here

Enough data, but low ceilings don't materially raise arrival delay. Typically well-drilled hubs or routine marine-layer and haze conditions.

AUS Austin 481 low-vis arrivals
OPO Porto 763 low-vis arrivals
LIM Lima 142 low-vis arrivals
LAX Los Angeles 1,269 low-vis arrivals
CPH Copenhagen 1,002 low-vis arrivals
MKE Milwaukee 357 low-vis arrivals
GIG Rio De Janeiro 40 low-vis arrivals
ALB Albany 191 low-vis arrivals
PEK Beijing 960 low-vis arrivals
OKA Naha 152 low-vis arrivals
PVG Shanghai 1,535 low-vis arrivals
CBR Canberra 52 low-vis arrivals
SIN Singapore 5,616 low-vis arrivals
HIJ Hiroshima 103 low-vis arrivals
MXP Milan 252 low-vis arrivals
BUR Burbank 68 low-vis arrivals
VCP Campinas 268 low-vis arrivals
ADL Adelaide 131 low-vis arrivals
CLE Cleveland 265 low-vis arrivals
OKC Oklahoma City 120 low-vis arrivals
KIX Osaka 377 low-vis arrivals
ICT Wichita 72 low-vis arrivals
GRU São Paulo 4,139 low-vis arrivals
BWI Baltimore 696 low-vis arrivals
PTY Tocumen 101 low-vis arrivals
LIS Lisbon 223 low-vis arrivals
DRW Darwin 262 low-vis arrivals
MEM Memphis 51 low-vis arrivals
PRG Prague 155 low-vis arrivals
CNF Belo Horizonte 208 low-vis arrivals
BDL Hartford 310 low-vis arrivals
GOT Göteborg 451 low-vis arrivals
AMS Amsterdam 1,820 low-vis arrivals
NGO Nagoya 152 low-vis arrivals
SFO San Francisco 11,891 low-vis arrivals
AEP Buenos Aires 1,517 low-vis arrivals
SHA Shanghai 858 low-vis arrivals
VNO Vilnius 62 low-vis arrivals
NRT Tokyo 4,287 low-vis arrivals
MCI Kansas City 218 low-vis arrivals
CHC Christchurch 210 low-vis arrivals
CMN Casablanca 478 low-vis arrivals
DAL Dallas 153 low-vis arrivals
KUL Kuala Lumpur 3,083 low-vis arrivals
CGH São Paulo 3,890 low-vis arrivals
ANC Anchorage 151 low-vis arrivals
GRR Grand Rapids 136 low-vis arrivals
LTN London 307 low-vis arrivals
ORF Norfolk 170 low-vis arrivals
DUS Düsseldorf 423 low-vis arrivals
ATL Atlanta 5,286 low-vis arrivals
TLL Tallinn 357 low-vis arrivals
EDI Edinburgh 395 low-vis arrivals
ATH Athens 98 low-vis arrivals
GDL Guadalajara 76 low-vis arrivals
YYC Calgary 736 low-vis arrivals
LIN Milan 117 low-vis arrivals
ICN Seoul 91 low-vis arrivals
VIE Vienna 93 low-vis arrivals
MUC Munich 1,049 low-vis arrivals
HND Tokyo 3,721 low-vis arrivals
MEX Mexico City 85 low-vis arrivals
DSM Des Moines 397 low-vis arrivals
SLC Salt Lake City 40 low-vis arrivals
SYR Syracuse 99 low-vis arrivals
OIT Oita 42 low-vis arrivals
HAM Hamburg 263 low-vis arrivals
YUL Montréal 525 low-vis arrivals
DOH Doha 204 low-vis arrivals
ZAG Zagreb 105 low-vis arrivals
BSB Brasília 180 low-vis arrivals
STL St Louis 290 low-vis arrivals
OSL Oslo 2,369 low-vis arrivals
RIX Riga 618 low-vis arrivals
HEL Helsinki 1,865 low-vis arrivals
AGA Agadir 73 low-vis arrivals
SDF Louisville 84 low-vis arrivals
ARN Stockholm 1,665 low-vis arrivals
JAX Jacksonville 227 low-vis arrivals
CVG Cincinnati / Covington 410 low-vis arrivals
BTV Burlington 126 low-vis arrivals
IGR Puerto Iguazu 134 low-vis arrivals
DTW Detroit 1,862 low-vis arrivals
RDU Raleigh/Durham 814 low-vis arrivals
SEA Seattle 3,203 low-vis arrivals
BRU Brussels 587 low-vis arrivals
LUX Luxembourg 374 low-vis arrivals
FRA Frankfurt am Main 442 low-vis arrivals
OMA Omaha 360 low-vis arrivals
PDX Portland 640 low-vis arrivals
BER Berlin 422 low-vis arrivals
SAV Savannah 98 low-vis arrivals
STN London 932 low-vis arrivals
OTP Bucharest 98 low-vis arrivals
RIC Richmond 285 low-vis arrivals
BNA Nashville 785 low-vis arrivals
BEG Belgrade 74 low-vis arrivals
FAR Fargo 77 low-vis arrivals
CHS Charleston 116 low-vis arrivals
LJU Ljubljana 66 low-vis arrivals
IND Indianapolis 410 low-vis arrivals
CGK Jakarta 3,017 low-vis arrivals
BIO Bilbao 284 low-vis arrivals
BOI Boise 161 low-vis arrivals
STR Stuttgart 76 low-vis arrivals
VCE Venezia 78 low-vis arrivals
OAK Oakland 713 low-vis arrivals
SJC San Jose 120 low-vis arrivals
SNA Santa Ana 59 low-vis arrivals
SAN San Diego 610 low-vis arrivals

Still accumulating data

SMF Sacramento 38 low-vis arrivals so far
UIO Quito 36 low-vis arrivals so far
ONT Ontario 36 low-vis arrivals so far
SCL Santiago 35 low-vis arrivals so far
LIT Little Rock 34 low-vis arrivals so far
ACE San Bartolomé 31 low-vis arrivals so far
DPS Kuta 30 low-vis arrivals so far
PER Perth 30 low-vis arrivals so far
ABQ Albuquerque 29 low-vis arrivals so far
NCE Nice 28 low-vis arrivals so far
AKJ Asahikawa 27 low-vis arrivals so far
OBO Obihiro 26 low-vis arrivals so far
BUD Budapest 25 low-vis arrivals so far
VLC Valencia 24 low-vis arrivals so far
MAH Mahón 23 low-vis arrivals so far
FSZ Shizuoka 23 low-vis arrivals so far
NBO Nairobi 23 low-vis arrivals so far
NGS Nagasaki 22 low-vis arrivals so far
TUL Tulsa 22 low-vis arrivals so far
LGB Long Beach 21 low-vis arrivals so far
BOG Bogota 21 low-vis arrivals so far
STT Charlotte Amalie 20 low-vis arrivals so far
LCA Larnaca 20 low-vis arrivals so far
MTY Monterrey 19 low-vis arrivals so far