New Upgraded Points Study Reveals the Most Weather-Delayed U.S. Airports, Airlines During the Holidays

A five-year study found weather accounted for an average 21.9% of delayed flights at the 60 busiest U.S. airports during November–January from November 2021 through January 2026. San Francisco had the highest airport share at 40.3%, while Alaska Airlines led the nine airlines analyzed at 27.8%; the study describes historical patterns, not a forecast for this holiday season.

Analysis

The key limitation is denominator: the study reports weather’s share of flights already delayed, not each airline’s overall delay probability, cancellations, or financial cost. It therefore does not support a direct earnings estimate or a standalone short in United Airlines Holdings (UAL). The more useful signal is potential network concentration: repeated disruption at SFO or EWR could propagate through aircraft rotations and crew availability, making downstream delays matter more than the initial weather event. Verify UAL’s holiday schedule exposure at those airports before treating its higher historical share as a company-level disadvantage; airport-level results cannot establish current airline-specific exposure.

For the next 1–3 months, actual storm tracks, FAA flow restrictions, and airline operational updates matter more than this backward-looking study. A weather disruption can raise reaccommodation and operating costs, but could also shift bookings to unaffected routes or carriers; the net revenue effect is not established here. Over 6–18 months, the durable question is whether network design and recovery performance reduce disruption spillovers—not whether one five-year ranking persists. The contrarian read is that headline rankings may overstate differentiation: weather attribution among delayed flights can move without a change in total operational reliability. No trade is justified from the release alone.

Key Decisions for Investors

• Do not trade UAL or Southwest Airlines (LUV) on the ranking alone. Treat it as a monitoring signal, not an earnings forecast.
• Before any relative UAL-versus-LUV position, compare current holiday departures and connection exposure at SFO, EWR, and other weather-sensitive hubs, then monitor actual cancellation and delay rates during storm events. The study does not supply these airline-specific inputs.
• If near-term forecasts coincide with unusually high UAL schedule exposure at SFO/EWR, consider a short-duration relative underweight in UAL versus LUV rather than an outright airline short; keep sizing small because disruption attribution and recovery costs are unquantified.
• Falsify the relative-risk thesis if UAL maintains comparable or better cancellation, on-time, and recovery metrics through material weather events, or if schedule data shows limited exposure at the cited airports. Reassess after holiday-season operating data, not from the historical ranking.