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 21:05 UTC.

Airport	Forecast	Window	Historical impact in these conditions
BKK Bangkok	Low (IFR)	Sat 15:00 → Sat 19:00 local	arrivals late 24% → 64%
ORY Paris	Low (IFR) (30% prob)	Sat 07:00 → Sat 10:00 local	arrivals late 24% → 57% · 2.3× cancellations
DMK Bangkok	Low (IFR)	Sat 15:00 → Sat 19:00 local	arrivals late 12% → 41%
TPA Tampa	Low (IFR)	Fri 17:05 → Fri 20:00 local	arrivals late 26% → 44% · 2.3× cancellations
VIE Vienna	Very low (LIFR)	Sat 04:00 → Sat 09:00 local	arrivals late 22% → 38% · 3.0× cancellations
HKG Hong Kong	Low (IFR)	Sat 16:00 → Sat 20:00 local	arrivals late 26% → 42% · 3.7× cancellations
SRQ Sarasota/Bradenton	Low (IFR)	Fri 17:05 → Fri 19:00 local	arrivals late 22% → 36%
AUH Abu Dhabi	Low (IFR) (30% prob)	Sat 03:00 → Sat 08:00 local	arrivals late 27% → 37%
CDG Paris	Low (IFR)	Sat 06:00 → Sat 09:00 local	arrivals late 20% → 30% · 1.4× 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 21% → 89%

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	21%	+3.7m	0.7%	41,931
Marginal (MVFR)	48%	+41.2m	0.9%	287
Low (IFR)	89%	+62.3m	0.0%	44
Very low (LIFR)	—	—	—	0

BNE Brisbane

Clear air vs low visibility: arrivals late 17% → 64%

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	17%	+3.7m	3.0%	15,693
Marginal (MVFR)	13%	-1.8m	4.4%	148
Low (IFR)	15%	-2.8m	0.0%	13
Very low (LIFR)	76%	+66.2m	1.9%	51

CAN Guangzhou

Clear air vs low visibility: arrivals late 17% → 59% · cancellations 8.7×

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	17%	-2.9m	1.3%	30,327
Marginal (MVFR)	28%	+12.7m	3.1%	4,436
Low (IFR)	63%	+35.4m	12%	131
Very low (LIFR)	25%	+0.5m	0.0%	16

BKK Bangkok

Clear air vs low visibility: arrivals late 24% → 64%

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	24%	+6.3m	16%	35,246
Marginal (MVFR)	45%	+20.5m	17%	611
Low (IFR)	64%	+34.3m	18%	276
Very low (LIFR)	70%	+24.8m	13%	20

FLL Fort Lauderdale

Clear air vs low visibility: arrivals late 24% → 60%

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	24%	+8.4m	2.3%	10,247
Marginal (MVFR)	42%	+35.6m	4.4%	367
Low (IFR)	33%	+3.1m	4.5%	21
Very low (LIFR)	86%	+137.0m	0.0%	21

PHL Philadelphia

Clear air vs low visibility: arrivals late 26% → 60% · cancellations 2.2×

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	26%	+12.5m	0.1%	26,388
Marginal (MVFR)	36%	+27.2m	0.1%	2,695
Low (IFR)	60%	+68.5m	0.3%	655
Very low (LIFR)	—	—	—	0

ORY Paris

Clear air vs low visibility: arrivals late 24% → 57% · cancellations 2.3×

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	24%	+6.5m	0.6%	17,721
Marginal (MVFR)	23%	+7.1m	0.7%	673
Low (IFR)	57%	+29.0m	1.5%	65
Very low (LIFR)	—	—	—	0

IAH Houston

Clear air vs low visibility: arrivals late 17% → 48%

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	17%	+1.6m	0.7%	37,695
Marginal (MVFR)	23%	+8.6m	0.2%	1,627
Low (IFR)	52%	+30.5m	0.0%	122
Very low (LIFR)	44%	+30.5m	0.8%	114

MNL Manila

Clear air vs low visibility: arrivals late 17% → 48%

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	17%	-1.3m	0.1%	9,543
Marginal (MVFR)	26%	+7.9m	0.2%	3,379
Low (IFR)	44%	+27.6m	0.0%	209
Very low (LIFR)	100%	+65.9m	0.0%	14

DMK Bangkok

Clear air vs low visibility: arrivals late 12% → 41%

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	12%	-1.8m	25%	14,645
Marginal (MVFR)	25%	+6.8m	22%	295
Low (IFR)	45%	+14.8m	21%	78
Very low (LIFR)	32%	+11.0m	24%	31

AYT Antalya

Clear air vs low visibility: arrivals late 21% → 50% · cancellations 7.0×

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	21%	+8.6m	0.3%	24,100
Marginal (MVFR)	23%	+13.1m	0.4%	683
Low (IFR)	50%	+24.8m	2.3%	42
Very low (LIFR)	—	—	—	0

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	1.3%	31,103
Marginal (MVFR)	34%	+30.8m	1.8%	354
Low (IFR)	61%	+116.9m	0.0%	57
Very low (LIFR)	45%	+44.7m	1.1%	186

PRG Prague

Clear air vs low visibility: arrivals late 20% → 41% · cancellations 7.4×

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	20%	+3.6m	0.6%	11,768
Marginal (MVFR)	19%	+2.4m	0.3%	303
Low (IFR)	45%	+17.7m	5.5%	138
Very low (LIFR)	21%	+0.9m	0.0%	28

BUF Buffalo

Clear air vs low visibility: arrivals late 25% → 45% · cancellations 1.2×

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	25%	+10.3m	2.4%	2,101
Marginal (MVFR)	28%	+13.9m	1.8%	334
Low (IFR)	42%	+23.1m	3.5%	53
Very low (LIFR)	58%	+20.0m	0.0%	12

TPA Tampa

Clear air vs low visibility: arrivals late 26% → 44% · cancellations 2.3×

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	26%	+12.0m	1.0%	5,882
Marginal (MVFR)	32%	+20.2m	0.0%	164
Low (IFR)	46%	+36.1m	2.9%	99
Very low (LIFR)	32%	+45.5m	0.0%	19

GMP Seoul

Clear air vs low visibility: arrivals late 12% → 29% · cancellations 2.7×

Ceiling / visibility	% arrivals delayed >15m	Avg delay	Cancelled	Flights
Clear (VFR)	12%	-1.9m	1.4%	1,569
Marginal (MVFR)	13%	-0.5m	0.3%	674
Low (IFR)	29%	+6.7m	0.0%	110
Very low (LIFR)	31%	+10.1m	28%	13

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. 1,965,943 origin↔destination pairs matched. Each origin is compared with its own clear-weather baseline.

Across 201 origins with enough history, the median within-origin effect of low ceilings at departure is +1.8 percentage points of late arrivals at a clear destination (an effect at only 112 of 201). 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

MSY New Orleans 17% → 75% of arrivals from here run late once its ceilings drop (55 low-vis departures)
MCO Orlando 23% → 79% of arrivals from here run late once its ceilings drop (52 low-vis departures)
BCN Barcelona 25% → 75% of arrivals from here run late once its ceilings drop (61 low-vis departures)
BRC San Carlos de Bariloche 24% → 66% of arrivals from here run late once its ceilings drop (96 low-vis departures)
MUC Munich 21% → 62% of arrivals from here run late once its ceilings drop (85 low-vis departures)
BNE Brisbane 17% → 57% of arrivals from here run late once its ceilings drop (23 low-vis departures)
SRQ Sarasota/Bradenton 14% → 48% of arrivals from here run late once its ceilings drop (27 low-vis departures)
IAH Houston 19% → 52% of arrivals from here run late once its ceilings drop (91 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% → 82%	27% → 17%	34
MM (MM)	OKA Naha	2.4% → 82%	15% → 0.0%	33
NU (NU)	OKA Naha	2.0% → 78%	23% → 46%	59
6J (6J)	OKA Naha	0.6% → 76%	12% → 0.0%	25
JL (JL)	OKA Naha	1.9% → 76%	44% → 75%	50
NH (NH)	OKA Naha	2.9% → 76%	22% → 10%	119
Air New Zealand (NZ)	WLG Wellington	1.9% → 22%	16% → 35%	211
JETSMART AIRLINES (WJ)	BRC San Carlos de Bariloche	1.7% → 16%	22% → 28%	38
中国国际航空公司 (CA)	SHA Shanghai	3.8% → 17%	14% → 11%	42
United Airlines (UA)	LGA New York	4.2% → 17%	29% → 40%	53
Shandong (SC)	PEK Beijing	1.6% → 13%	26% → 38%	39
Sounds Air (S8)	WLG Wellington	0.9% → 12%	3.0% → 21%	42
WestJet (WS)	YYZ Toronto	2.1% → 11%	14% → 21%	142
Air China (CA)	HGH Hangzhou	1.2% → 9.7%	27% → 25%	165

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)	+28.5m	+15.1m	41%	198,853
20–40 min (avg 27m)	+48.5m	+21.5m	51%	176,963
40–70 min (avg 51m)	+79.8m	+28.8m	60%	95,061
70+ min (avg 130m)	+152.5m	+22.5m	59%	76,346

Arrivals

Delay first posted	Actual delay (avg)	Grew by	Got ≥10 min worse	Flights
10–20 min (avg 14m)	+18.1m	+4.5m	21%	196,284
20–40 min (avg 28m)	+34.4m	+6.9m	24%	177,785
40–70 min (avg 52m)	+61.7m	+10.1m	30%	105,200
70+ min (avg 136m)	+141.1m	+5.5m	32%	97,498

Most optimistic first estimates (departures)

FLYBONDI +84 min beyond the first posted delay, on average · 88% get ≥10 min worse · 59 delayed departures
Bahamasair +79 min beyond the first posted delay, on average · 92% get ≥10 min worse · 87 delayed departures
Tus +65 min beyond the first posted delay, on average · 89% get ≥10 min worse · 166 delayed departures
AZIMUTH AIRLINES +58 min beyond the first posted delay, on average · 66% get ≥10 min worse · 203 delayed departures
Contour Aviation +51 min beyond the first posted delay, on average · 70% get ≥10 min worse · 328 delayed departures
金鹏航空 +49 min beyond the first posted delay, on average · 83% get ≥10 min worse · 107 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%	+10.7m	29,112
Clear now, IFR/LIFR 3–6 h ago	24%	+9.5m	50,264
Clear for 6+ h	23%	+6.3m	2,004,072

Slowest to recover

DCA Washington 28% → 66% of arrivals late in the 3 h after weather clears, vs steady clear air (190 arrivals)
COR Cordoba 22% → 47% of arrivals late in the 3 h after weather clears, vs steady clear air (34 arrivals)
PEK Beijing 19% → 43% of arrivals late in the 3 h after weather clears, vs steady clear air (607 arrivals)
BKK Bangkok 23% → 45% of arrivals late in the 3 h after weather clears, vs steady clear air (594 arrivals)
BOS Boston 25% → 44% of arrivals late in the 3 h after weather clears, vs steady clear air (373 arrivals)
CLE Cleveland 26% → 44% of arrivals late in the 3 h after weather clears, vs steady clear air (50 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, 3,182,671 arrivals so far.

By cloud-ceiling height

Band	% delayed >15m	Avg delay	Cancelled	Flights
<200 ft	34%	+22.8m	1.0%	886
200–500 ft	23%	+9.6m	2.4%	9,444
500–1,000 ft	24%	+7.9m	1.8%	47,791
1,000–2,500 ft	25%	+9.0m	1.5%	152,412
≥2,500 ft / none	23%	+6.6m	1.6%	2,972,138

By wind / gust speed

Band	% delayed >15m	Avg delay	Cancelled	Flights
<15 kt	22%	+6.2m	1.6%	2,826,925
15–24 kt	27%	+10.3m	1.4%	305,774
25–34 kt	33%	+16.6m	2.2%	46,072
≥35 kt	44%	+35.7m	11%	3,900

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.

DUB Dublin 755 low-vis arrivals
MEX Mexico City 84 low-vis arrivals
ROC Rochester 45 low-vis arrivals
AMS Amsterdam 552 low-vis arrivals
DUS Düsseldorf 128 low-vis arrivals
SHA Shanghai 480 low-vis arrivals
ADL Adelaide 136 low-vis arrivals
MAN Manchester 380 low-vis arrivals
PVG Shanghai 1,610 low-vis arrivals
NRT Tokyo 3,149 low-vis arrivals
HND Tokyo 3,582 low-vis arrivals
OKA Naha 89 low-vis arrivals
MUC Munich 117 low-vis arrivals
DCA Washington 551 low-vis arrivals
IAD Washington 700 low-vis arrivals
AVL Asheville 54 low-vis arrivals
LAX Los Angeles 2,668 low-vis arrivals
DPS Kuta 50 low-vis arrivals
PIT Pittsburgh 423 low-vis arrivals
MDW Chicago 450 low-vis arrivals
JAX Jacksonville 103 low-vis arrivals
STL St Louis 141 low-vis arrivals
GRU São Paulo 4,919 low-vis arrivals
CGH São Paulo 2,875 low-vis arrivals
YVR Vancouver 332 low-vis arrivals
TFN Tenerife 650 low-vis arrivals
HGH Hangzhou 664 low-vis arrivals
RIX Riga 237 low-vis arrivals
DTW Detroit 1,302 low-vis arrivals
YYC Calgary 488 low-vis arrivals
CLT Charlotte 2,699 low-vis arrivals
ORD Chicago 3,859 low-vis arrivals
LTN London 187 low-vis arrivals
ALB Albany 98 low-vis arrivals
IST Istanbul 764 low-vis arrivals
AEP Buenos Aires 1,422 low-vis arrivals
GDL Guadalajara 87 low-vis arrivals
CLE Cleveland 115 low-vis arrivals
ANC Anchorage 66 low-vis arrivals
HAM Hamburg 232 low-vis arrivals
DOH Doha 460 low-vis arrivals
ATL Atlanta 3,241 low-vis arrivals
EDI Edinburgh 548 low-vis arrivals
PDX Portland 194 low-vis arrivals
OPO Porto 570 low-vis arrivals
SDJ Sendai 91 low-vis arrivals
BSB Brasília 53 low-vis arrivals
LIN Milan 53 low-vis arrivals
LIS Lisbon 261 low-vis arrivals
LHR London 1,356 low-vis arrivals
KIX Osaka 482 low-vis arrivals
IGR Puerto Iguazu 104 low-vis arrivals
BOI Boise 148 low-vis arrivals
PTY Tocumen 66 low-vis arrivals
BWI Baltimore 192 low-vis arrivals
OSL Oslo 1,154 low-vis arrivals
YUL Montréal 180 low-vis arrivals
TLL Tallinn 166 low-vis arrivals
SEA Seattle 2,279 low-vis arrivals
CMN Casablanca 189 low-vis arrivals
BRU Brussels 153 low-vis arrivals
SAT San Antonio 103 low-vis arrivals
HEL Helsinki 1,050 low-vis arrivals
IND Indianapolis 206 low-vis arrivals
ARN Stockholm 606 low-vis arrivals
STN London 224 low-vis arrivals
CBR Canberra 41 low-vis arrivals
BDL Hartford 144 low-vis arrivals
CJU Jeju City 87 low-vis arrivals
BER Berlin 268 low-vis arrivals
SFO San Francisco 10,963 low-vis arrivals
AGA Agadir 50 low-vis arrivals
LUX Luxembourg 102 low-vis arrivals
DEN Denver 550 low-vis arrivals
OMA Omaha 172 low-vis arrivals
BNA Nashville 164 low-vis arrivals
RDU Raleigh/Durham 359 low-vis arrivals
CGK Jakarta 2,976 low-vis arrivals
MCI Kansas City 118 low-vis arrivals
SAV Savannah 68 low-vis arrivals
AUS Austin 332 low-vis arrivals
BIO Bilbao 190 low-vis arrivals
SAN San Diego 637 low-vis arrivals
MAH Mahón 58 low-vis arrivals
OAK Oakland 502 low-vis arrivals
GRR Grand Rapids 48 low-vis arrivals
WAW Warsaw 153 low-vis arrivals
LGW London 441 low-vis arrivals

Still accumulating data

CHS Charleston 38 low-vis arrivals so far
TAK Takamatsu 36 low-vis arrivals so far
FSD Sioux Falls 35 low-vis arrivals so far
GVA Geneva 33 low-vis arrivals so far
CRW Charleston 33 low-vis arrivals so far
JAC Jackson 31 low-vis arrivals so far
MSY New Orleans 31 low-vis arrivals so far
SNA Santa Ana 29 low-vis arrivals so far
CVG Cincinnati / Covington 27 low-vis arrivals so far
VCE Venezia 27 low-vis arrivals so far
UIO Quito 26 low-vis arrivals so far
KOJ Kagoshima 26 low-vis arrivals so far
MDZ Mendoza 26 low-vis arrivals so far
SYR Syracuse 26 low-vis arrivals so far
SCL Santiago 26 low-vis arrivals so far
NAP Napoli 25 low-vis arrivals so far
SJC San Jose 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
BCN Barcelona 22 low-vis arrivals so far
OKC Oklahoma City 22 low-vis arrivals so far
LCA Larnaca 22 low-vis arrivals so far
OTP Bucharest 21 low-vis arrivals so far