Name: Dense Fog in Colorado, May 31, 2026
Start: 2026-05-31T05:30
End: 2026-05-31T06:00
Location: Colorado

Where it happened

Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

Tornadoes
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Floods
Wind
Hail
Winter weather
Heat and drought
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Fire, smoke and dust
Marine and coastal
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The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 1

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS GJT wrote it up.

Over May 29 and 30, a shortwave trough brought light rain to numerous parts of the Intermountain West. Surface conditions remained unsaturated in spite of this, but portions of northern Colorado saw moisture linger into the morning of May 31. With this, as temperatures cooled and winds weakened overnight, the environment supported brief dense fog development within the Yampa River Basin.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Grand Junction, CO wrote its last area forecast discussion before the first event at May 30, 4:20 PM MST, 13 hours 10 minutes earlier.

Area forecast discussion, May 30, 4:20 PM MST, 13 hours 10 minutes before

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The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

1 dense fog. Local standard time, as filed.

Dense Fog, Central Yampa River Basin

When: May 31, 5:30 AM MST to 6:00 AM MST
Where: Central Yampa River Basin forecast zone
Reported by: ASOS
Coordinates: 40.361, -107.805 (the zone’s center; the record gives no point)

Localized dense fog developed within the Central Yampa River Basin during the morning of May 31. The KCAG ASOS at the Craig-Moffat County Airport reported a brief period spanning less than ten minutes of 1/4-mile visibility due to dense fog. No reports of injuries, damages, or fatalities were received.

What these are

Dense Fog: Fog reducing visibility to a quarter mile or less, filed where it caused accidents or disruption.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in Colorado in 2026 Every state in 2026 This day in weather history Warnings in Colorado, May 2026

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-30. Each event’s entry at NCEI: 1341438.