Today | Weather | Wednesday, March 18, 2026

Active Weather Warnings

Weather in Fort Collins, Colorado

08:58 AM

Now

52° F

Feels Like 54°

Precipitation 0 %

Wind 6 mph

UV Index (0 - 11+) 2

Humidity 41 %

Today

Day 82°

Night 43°

Precipitation 1 %

Wind 10 mph

UV Index (0 - 11+) 5

Fort Collins Weather Forecast Updated

Last updated on March 18, 2026 at 7:29 AM

Weather Forecast History

Last Year's Weather on This Day (March 18, 2025)

Day

63°

Night

30°

Wind

17 mph

UV Index

Precipitation

60 %

Air Quality in Fort Collins

NOW

33 AQI

Good air quality Dominant pollutant: O₃

Pollutant Concentrations:

PM_2.5 0.87 µg/m³

PM₁₀ 1.52 µg/m³

O₃ 0.036 ppm

NO₂ 0.9 ppb

SO₂ 0.2 ppb

CO 0.08 ppm

NH₃ 0.58 µg/m³

NO 0.45 µg/m³

PM_2.5 – Fine particles <2.5μm

PM₁₀ – Inhalable particles <10μm

O₃ – Ozone

NO₂ – Nitrogen dioxide

SO₂ – Sulfur dioxide

CO – Carbon monoxide

NH₃ – Ammonia

NO – Nitric oxide

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

Show raw pollutant concentrations (µg/m³)

PM_2.5 – 0.87 µg/m³

PM₁₀ – 1.52 µg/m³

O₃ – 70.47 µg/m³

NO₂ – 1.68 µg/m³

SO₂ – 0.62 µg/m³

CO – 96.12 µg/m³

NH₃ – 0.58 µg/m³

NO – 0.45 µg/m³

View Hourly Air Quality Forecast

Weather Alerts and Warnings for Fort Collins

Severe Future Possible

Fire Weather Watch

Fire Weather Watch issued March 17 at 2:16AM MDT until March 18 at 7:00PM MDT by NWS Denver CO

Mar 18, 12:00 PM → Mar 18, 7:00 PM

* AFFECTED AREA...Fire Weather Zones 238, 242, 244, 248, 249,
250 and 251.

* TIMING...For the Red Flag Warning, from 10 AM this morning to
8 PM MDT this evening. For the Fire Weather Watch, from
Wednesday afternoon through Wednesday evening.

* WINDS...Northwest 20 to 30 mph with gusts up to 45 mph.

* RELATIVE HUMIDITY...As low as 14 percent. On Wednesday, as low
as 11 percent.

IMPACTS: Conditions will be favorable for rapid fire spread.
Avoid outdoor burning and any activity that may produce a
spark and start a wildfire.

+ Read More

A Red Flag Warning means that critical fire weather conditions are either occurring now....or will shortly. A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. A Fire Weather Watch means that critical fire weather conditions are forecast to occur. Listen for later forecasts and possible Red Flag Warnings.

Updated: Mar 17, 12:05 PM Source: NWS Alert

Severe Expected Likely

Red Flag Warning

Red Flag Warning issued March 18 at 3:36AM MDT until March 18 at 7:00PM MDT by NWS Denver CO

Mar 18, 11:00 AM → Mar 18, 7:00 PM

* AFFECTED AREA...Fire Weather Zones 238 and 242.

* TIMING...For the Red Flag Warning, from 11 AM this morning to
7 PM MDT this evening. For the Fire Weather Watch, from
Thursday morning through Thursday evening.

* WINDS...Northwest 15 to 25 mph with gusts up to 40 mph. On
Thursday, northwest wind gusts up to 30 mph.

* RELATIVE HUMIDITY...As low as 8 percent both days.

IMPACTS: Conditions will be favorable for rapid fire spread.
Avoid outdoor burning and any activity that may produce a
spark and start a wildfire.