KHVN — Tweed New Haven Airport

fog forecast & climatology · New Haven city page · full 10-year analysis →
No fog signal in NWS guidance for the next 48 hours. dense fog (visibility under a mile) is rare here in September.forecast cycle 2026-09-04T13:00:00Z · page rebuilt daily · live layers below update hourly

Fog hours per year
65 h below CAT I minima (2016–2026 average)
Fog season
February and May
Typical fog event
~2 h once it forms (middle half 1–3 h, n=292)
Data through
2026-08-15 · machine-readable data.json

When this airport fogs in

In a typical year Tweed New Haven Airport spends 65 hours below CAT I approach minima (visibility under ~½ mile or ceiling under 200 ft), concentrated in February and May. The strip above shows the hour-by-hour pattern for the current month from ten years of weather observations.

Fog season

January: ~8 hJanFebruary: ~10 hFebMarch: ~9 hMarApril: ~4 hAprMay: ~9 hMayJune: ~7 hJunJuly: ~1 hJulAugust: ~1 hAugSeptember: ~0 hSepOctober: ~3 hOctNovember: ~2 hNovDecember: ~9 hDec
Fog season is January, February, March, April, May, June, October, December, peaking in February; fog is mostly a 1 AM–9 AM phenomenon; typically thinning out by 11 AM; a typical event lasts about 2 hours once it forms local time · 10-yr average

Runway infrastructure

endapproach lightsbest approachlengthRVR
02MALSFCAT I5,600 ftRVR
20—LPV5,600 ftRVR

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 — receipts on the scorecard. Methodology.

Sources: NOAA/NWS National Blend of Models guidance · METAR observations 2016–2026 (Iowa Environmental Mesonet) · FAA NASR. Machine access: data.json · llms.txt. Not for operational use.