KMDW — Chicago Midway International Airport
fog forecast & climatology · full 10-year analysis →
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When this airport fogs in
In a typical year Chicago Midway International Airport spends 13 hours below CAT I approach minima (visibility under ~½ mile or ceiling under 200 ft), concentrated in January and February. The strip above shows the hour-by-hour pattern for the current month from ten years of weather observations.
Runway infrastructure
| end | approach lights | best approach | length | RVR |
|---|---|---|---|---|
| 04L | — | — | 5,507 ft | — |
| 22R | — | LPV | 5,507 ft | — |
| 04R | — | CAT I | 6,445 ft | RVR |
| 22L | — | — | 6,445 ft | RVR |
| 13L | RLLS | CAT I | 6,522 ft | RVR |
| 31R | RLLS | CAT I | 6,522 ft | RVR |
| 13R | — | — | 3,859 ft | — |
| 31L | — | — | 3,859 ft | — |
From FAA NASR / curated AIP Canada research. Approach-light class and minima tier drive how low an approach can be flown — details in the chase board.
For flight operations
EFVS crews: the CHASE board ranks airports by live fog status, approach lighting, go-around height and flight time from your base. Forecast probabilities publish here per-airport once the calibrated model beats climatology on live verification — until then this page shows NWS guidance wording and measured climatology only. Methodology & verification.
Sources: NOAA/NWS National Blend of Models guidance · 10 years of METAR observations (Iowa Environmental Mesonet) · FAA NASR. Not for operational use.