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 13:11 UTC.

Airport	Forecast	Window	Historical impact in these conditions
BKK Bangkok	Low (IFR)	Thu 16:00 → Thu 21:00 local	arrivals late 24% → 68%
PHL Philadelphia	Low (IFR)	Wed 09:11 → Wed 12:00 local	arrivals late 25% → 61% · 2.4× cancellations
DMK Bangkok	Low (IFR)	Thu 16:00 → Thu 21:00 local	arrivals late 13% → 41%
BUF Buffalo	Low (IFR) (30% prob)	Wed 19:00 → Wed 23:00 local	arrivals late 25% → 44% · 1.3× cancellations
TPA Tampa	Low (IFR)	Wed 15:00 → Wed 19:00 local	arrivals late 26% → 44% · 2.5× cancellations
SRQ Sarasota/Bradenton	Low (IFR)	Wed 18:00 → Wed 20:00 local	arrivals late 23% → 39%
ITM Osaka	Low (IFR)	Thu 12:00 → Thu 18:00 local	arrivals late 19% → 35%
HKG Hong Kong	Low (IFR)	Thu 20:00 → Thu 23:00 local	arrivals late 28% → 44% · 3.7× cancellations
EWR New York	Low (IFR)	Wed 09:11 → Wed 10:00 local	arrivals late 21% → 36% · 1.7× cancellations
HPN White Plains	Low (IFR)	Wed 09:11 → Wed 10:00 local	arrivals late 39% → 52% · 1.4× cancellations
AUH Abu Dhabi	Low (IFR)	Thu 03:00 → Thu 09:00 local	arrivals late 27% → 38%
CTS Sapporo	Very low (LIFR)	Wed 22:11 → Wed 23:00 local	arrivals late 19% → 30% · 4.7× cancellations

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.

PHX Phoenix

Clear air vs low visibility: arrivals late 22% → 89%

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	22%	+4.9m	0.6%	42,596
Marginal (MVFR)	48%	+41.2m	0.9%	287
Low (IFR)	89%	+62.3m	0.0%	44
Very low (LIFR)	—	—	—	0

BKK Bangkok

Clear air vs low visibility: arrivals late 24% → 68%

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	24%	+6.2m	16%	34,262
Marginal (MVFR)	39%	+15.6m	17%	680
Low (IFR)	68%	+36.4m	14%	253
Very low (LIFR)	70%	+24.8m	13%	20

CAN Guangzhou

Clear air vs low visibility: arrivals late 20% → 59% · cancellations 7.5×

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	20%	+0.8m	1.4%	24,330
Marginal (MVFR)	31%	+15.7m	3.1%	3,983
Low (IFR)	63%	+35.4m	12%	131
Very low (LIFR)	25%	+0.5m	0.0%	16

PHL Philadelphia

Clear air vs low visibility: arrivals late 25% → 61% · cancellations 2.4×

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	25%	+12.1m	0.1%	27,345
Marginal (MVFR)	34%	+24.7m	0.1%	2,731
Low (IFR)	61%	+71.8m	0.3%	621
Very low (LIFR)	56%	+14.4m	0.0%	9

MNL Manila

Clear air vs low visibility: arrivals late 18% → 52%

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	18%	-0.5m	0.2%	7,726
Marginal (MVFR)	27%	+8.9m	0.2%	2,905
Low (IFR)	48%	+31.8m	0.0%	182
Very low (LIFR)	100%	+65.9m	0.0%	14

ORY Paris

Clear air vs low visibility: arrivals late 24% → 57% · cancellations 2.1×

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	24%	+6.5m	0.7%	15,539
Marginal (MVFR)	22%	+7.0m	0.7%	689
Low (IFR)	57%	+27.8m	1.4%	69
Very low (LIFR)	—	—	—	0

IAH Houston

Clear air vs low visibility: arrivals late 17% → 46%

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	17%	+1.6m	0.6%	38,239
Marginal (MVFR)	20%	+4.6m	0.1%	2,119
Low (IFR)	48%	+27.4m	0.0%	131
Very low (LIFR)	44%	+30.5m	0.8%	114

AYT Antalya

Clear air vs low visibility: arrivals late 21% → 50% · cancellations 7.6×

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	21%	+9.0m	0.3%	21,116
Marginal (MVFR)	24%	+15.4m	0.0%	514
Low (IFR)	50%	+24.8m	2.3%	42
Very low (LIFR)	—	—	—	0

DMK Bangkok

Clear air vs low visibility: arrivals late 13% → 41%

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	13%	-1.3m	24%	12,849
Marginal (MVFR)	29%	+9.0m	22%	254
Low (IFR)	45%	+14.8m	21%	78
Very low (LIFR)	32%	+11.0m	24%	31

MCO Orlando

Clear air vs low visibility: arrivals late 23% → 49%

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	23%	+4.4m	1.2%	32,224
Marginal (MVFR)	36%	+34.2m	1.9%	331
Low (IFR)	61%	+116.9m	0.0%	57
Very low (LIFR)	45%	+44.7m	1.1%	186

DFW Dallas-Fort Worth

Clear air vs low visibility: arrivals late 24% → 47%

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	24%	+10.1m	0.0%	69,037
Marginal (MVFR)	24%	+16.6m	0.0%	4,008
Low (IFR)	47%	+48.9m	0.0%	503
Very low (LIFR)	—	—	—	0

WLG Wellington

Clear air vs low visibility: arrivals late 14% → 34% · cancellations 13.6×

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	14%	+0.3m	1.5%	668
Marginal (MVFR)	23%	+7.5m	2.9%	336
Low (IFR)	37%	+18.2m	16%	54
Very low (LIFR)	14%	+20.7m	46%	7

PRG Prague

Clear air vs low visibility: arrivals late 20% → 39% · cancellations 7.4×

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	20%	+3.9m	0.6%	10,665
Marginal (MVFR)	19%	+2.2m	0.3%	322
Low (IFR)	42%	+16.4m	5.2%	147
Very low (LIFR)	21%	+0.9m	0.0%	28

BUF Buffalo

Clear air vs low visibility: arrivals late 25% → 44% · cancellations 1.3×

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	25%	+10.6m	2.4%	1,737
Marginal (MVFR)	28%	+16.2m	2.4%	244
Low (IFR)	42%	+23.1m	3.5%	53
Very low (LIFR)	56%	+16.9m	0.0%	9

TPA Tampa

Clear air vs low visibility: arrivals late 26% → 44% · cancellations 2.5×

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	26%	+11.3m	1.0%	6,249
Marginal (MVFR)	28%	+17.5m	0.0%	160
Low (IFR)	46%	+36.1m	2.9%	99
Very low (LIFR)	32%	+45.5m	0.0%	19

MEL Melbourne

Clear air vs low visibility: arrivals late 22% → 39% · cancellations 2.4×

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	22%	+6.5m	1.3%	18,228
Marginal (MVFR)	29%	+10.3m	2.3%	3,065
Low (IFR)	28%	+10.3m	2.2%	617
Very low (LIFR)	56%	+38.4m	4.8%	411

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. 1,908,206 origin↔destination pairs matched. Each origin is compared with its own clear-weather baseline.

Across 190 origins with enough history, the median within-origin effect of low ceilings at departure is +0.3 percentage points of late arrivals at a clear destination (an effect at only 98 of 190). 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 1.7% when the origin is LIFR. The heavy exporters:

Origins that export the most delay when their ceilings drop

MCO Orlando 22% → 79% of arrivals from here run late once its ceilings drop (52 low-vis departures)
TPA Tampa 20% → 68% of arrivals from here run late once its ceilings drop (59 low-vis departures)
SRQ Sarasota/Bradenton 14% → 59% of arrivals from here run late once its ceilings drop (22 low-vis departures)
MSY New Orleans 18% → 63% of arrivals from here run late once its ceilings drop (30 low-vis departures)
BRC San Carlos de Bariloche 23% → 66% of arrivals from here run late once its ceilings drop (96 low-vis departures)
SZX Shenzhen 29% → 64% of arrivals from here run late once its ceilings drop (188 low-vis departures)
DFW Dallas-Fort Worth 32% → 63% of arrivals from here run late once its ceilings drop (144 low-vis departures)
BKK Bangkok 19% → 48% of arrivals from here run late once its ceilings drop (62 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	0.9% → 100%	26% → —	28
MM (MM)	OKA Naha	3.2% → 96%	14% → 0.0%	28
JL (JL)	OKA Naha	2.6% → 93%	42% → 67%	41
NH (NH)	OKA Naha	3.8% → 94%	21% → 0.0%	96
NU (NU)	OKA Naha	2.6% → 90%	25% → 60%	51
Air New Zealand (NZ)	WLG Wellington	1.8% → 25%	17% → 45%	189
JETSMART AIRLINES (WJ)	BRC San Carlos de Bariloche	1.6% → 16%	22% → 28%	38
Sounds Air (S8)	WLG Wellington	1.0% → 14%	3.2% → 30%	36
Air China (CA)	SHA Shanghai	4.4% → 17%	14% → 12%	41
SC (SC)	PEK Beijing	1.7% → 13%	26% → 38%	39
Air China (CA)	HGH Hangzhou	1.2% → 10%	27% → 25%	159
WestJet (WS)	YYZ Toronto	2.1% → 11%	14% → 23%	150
CemAir (5Z)	JNB Johannesburg	2.4% → 11%	24% → 42%	28
United Airlines (UA)	LGA New York	4.3% → 12%	29% → 39%	49

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 16:49 on average. Tracking since 2026-06-29. 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)	+28.6m	+15.3m	41%	174,442
20–40 min (avg 27m)	+48.7m	+21.8m	52%	156,280
40–70 min (avg 51m)	+80.1m	+29.1m	60%	85,000
70+ min (avg 130m)	+152.6m	+22.8m	60%	68,327

Arrivals

Delay first posted	Actual delay (avg)	Grew by	Got ≥10 min worse	Flights
10–20 min (avg 14m)	+18.3m	+4.7m	21%	171,253
20–40 min (avg 28m)	+34.6m	+7.1m	25%	157,381
40–70 min (avg 52m)	+61.9m	+10.2m	30%	94,032
70+ min (avg 136m)	+141.1m	+5.6m	32%	87,903

Most optimistic first estimates (departures)

FLYBONDI +84 min beyond the first posted delay, on average · 88% get ≥10 min worse · 59 delayed departures
Bahamasair +78 min beyond the first posted delay, on average · 92% get ≥10 min worse · 85 delayed departures
AZIMUTH AIRLINES +63 min beyond the first posted delay, on average · 68% get ≥10 min worse · 180 delayed departures
Tus +62 min beyond the first posted delay, on average · 89% get ≥10 min worse · 152 delayed departures
Contour Aviation +52 min beyond the first posted delay, on average · 70% get ≥10 min worse · 301 delayed departures
金鹏航空 +50 min beyond the first posted delay, on average · 83% get ≥10 min worse · 104 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	26%	+11.1m	29,093
Clear now, IFR/LIFR 3–6 h ago	24%	+9.5m	52,394
Clear for 6+ h	23%	+6.4m	2,024,187

Slowest to recover

DCA Washington 28% → 66% of arrivals late in the 3 h after weather clears, vs steady clear air (189 arrivals)
CAN Guangzhou 19% → 49% of arrivals late in the 3 h after weather clears, vs steady clear air (262 arrivals)
BKK Bangkok 23% → 50% of arrivals late in the 3 h after weather clears, vs steady clear air (511 arrivals)
COR Cordoba 23% → 47% of arrivals late in the 3 h after weather clears, vs steady clear air (34 arrivals)
PEK Beijing 20% → 43% of arrivals late in the 3 h after weather clears, vs steady clear air (607 arrivals)
PHL Philadelphia 25% → 46% of arrivals late in the 3 h after weather clears, vs steady clear air (386 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, 2,781,020 arrivals so far.

By cloud-ceiling height

Band	% delayed >15m	Avg delay	Cancelled	Flights
<200 ft	38%	+29.2m	1.1%	699
200–500 ft	23%	+9.6m	2.4%	8,296
500–1,000 ft	25%	+8.4m	1.9%	42,398
1,000–2,500 ft	25%	+9.2m	1.5%	134,049
≥2,500 ft / none	23%	+7.2m	1.6%	2,595,578

By wind / gust speed

Band	% delayed >15m	Avg delay	Cancelled	Flights
<15 kt	23%	+6.7m	1.6%	2,474,667
15–24 kt	27%	+11.1m	1.5%	261,719
25–34 kt	34%	+17.2m	2.3%	41,338
≥35 kt	46%	+39.5m	12%	3,296

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.

ADL Adelaide 143 low-vis arrivals
GOT Göteborg 68 low-vis arrivals
DTW Detroit 975 low-vis arrivals
HND Tokyo 2,993 low-vis arrivals
RIX Riga 188 low-vis arrivals
LAX Los Angeles 3,107 low-vis arrivals
DSM Des Moines 147 low-vis arrivals
CLE Cleveland 105 low-vis arrivals
CGH São Paulo 2,394 low-vis arrivals
NRT Tokyo 2,958 low-vis arrivals
AMS Amsterdam 510 low-vis arrivals
DPS Kuta 50 low-vis arrivals
CPH Copenhagen 389 low-vis arrivals
GRU São Paulo 4,237 low-vis arrivals
MSP Minneapolis 331 low-vis arrivals
SHA Shanghai 459 low-vis arrivals
HGH Hangzhou 664 low-vis arrivals
MDW Chicago 464 low-vis arrivals
MEX Mexico City 91 low-vis arrivals
PVG Shanghai 1,610 low-vis arrivals
YVR Vancouver 332 low-vis arrivals
IAD Washington 723 low-vis arrivals
DCA Washington 540 low-vis arrivals
CLT Charlotte 2,699 low-vis arrivals
LTN London 163 low-vis arrivals
IST Istanbul 1,121 low-vis arrivals
PIT Pittsburgh 424 low-vis arrivals
DUB Dublin 927 low-vis arrivals
STN London 136 low-vis arrivals
EDI Edinburgh 468 low-vis arrivals
ALB Albany 95 low-vis arrivals
LHR London 1,708 low-vis arrivals
ORD Chicago 3,887 low-vis arrivals
DOH Doha 460 low-vis arrivals
LIS Lisbon 251 low-vis arrivals
GDL Guadalajara 77 low-vis arrivals
MAN Manchester 513 low-vis arrivals
AEP Buenos Aires 1,397 low-vis arrivals
CVG Cincinnati / Covington 50 low-vis arrivals
ATL Atlanta 3,352 low-vis arrivals
AVL Asheville 49 low-vis arrivals
HAM Hamburg 209 low-vis arrivals
YUL Montréal 115 low-vis arrivals
OPO Porto 515 low-vis arrivals
MUC Munich 181 low-vis arrivals
PTY Tocumen 66 low-vis arrivals
BOI Boise 151 low-vis arrivals
HEL Helsinki 1,030 low-vis arrivals
DUS Düsseldorf 210 low-vis arrivals
OSL Oslo 1,091 low-vis arrivals
BWI Baltimore 192 low-vis arrivals
CBR Canberra 41 low-vis arrivals
LUX Luxembourg 104 low-vis arrivals
SEA Seattle 2,324 low-vis arrivals
IGR Puerto Iguazu 94 low-vis arrivals
TPE Taipei 404 low-vis arrivals
OMA Omaha 151 low-vis arrivals
IND Indianapolis 227 low-vis arrivals
BDL Hartford 125 low-vis arrivals
ARN Stockholm 562 low-vis arrivals
TLL Tallinn 159 low-vis arrivals
BER Berlin 276 low-vis arrivals
CJU Jeju City 87 low-vis arrivals
KIX Osaka 252 low-vis arrivals
SFO San Francisco 11,620 low-vis arrivals
ANC Anchorage 79 low-vis arrivals
SAT San Antonio 107 low-vis arrivals
LIN Milan 40 low-vis arrivals
CMN Casablanca 132 low-vis arrivals
TFN Tenerife 444 low-vis arrivals
DEN Denver 550 low-vis arrivals
BRU Brussels 318 low-vis arrivals
SDJ Sendai 57 low-vis arrivals
BNA Nashville 183 low-vis arrivals
RDU Raleigh/Durham 357 low-vis arrivals
CGK Jakarta 2,848 low-vis arrivals
FRA Frankfurt am Main 64 low-vis arrivals
MCI Kansas City 119 low-vis arrivals
SAV Savannah 44 low-vis arrivals
AGA Agadir 56 low-vis arrivals
AUS Austin 345 low-vis arrivals
GRR Grand Rapids 43 low-vis arrivals
BIO Bilbao 174 low-vis arrivals
MAH Mahón 58 low-vis arrivals
SAN San Diego 659 low-vis arrivals
OAK Oakland 508 low-vis arrivals
WAW Warsaw 163 low-vis arrivals
LGW London 637 low-vis arrivals

Still accumulating data

FSD Sioux Falls 38 low-vis arrivals so far
SCL Santiago 38 low-vis arrivals so far
CHS Charleston 37 low-vis arrivals so far
OTP Bucharest 36 low-vis arrivals so far
ROC Rochester 36 low-vis arrivals so far
TNG Tangier 35 low-vis arrivals so far
GVA Geneva 33 low-vis arrivals so far
UIO Quito 31 low-vis arrivals so far
JAC Jackson 31 low-vis arrivals so far
CRW Charleston 30 low-vis arrivals so far
CNF Belo Horizonte 29 low-vis arrivals so far
DUR Durban 29 low-vis arrivals so far
SNA Santa Ana 29 low-vis arrivals so far
FLL Fort Lauderdale 27 low-vis arrivals so far
VCE Venezia 27 low-vis arrivals so far
LCA Larnaca 27 low-vis arrivals so far
MDZ Mendoza 26 low-vis arrivals so far
OKA Naha 25 low-vis arrivals so far
NAP Napoli 25 low-vis arrivals so far
SJC San Jose 24 low-vis arrivals so far
GIG Rio De Janeiro 24 low-vis arrivals so far
BHM Birmingham 24 low-vis arrivals so far
MCT Muscat/Seeb 24 low-vis arrivals so far
KUH Kushiro 23 low-vis arrivals so far