Today | Weather | Monday, July 20, 2026
Active Weather Warnings

Weather in Sioux City, Iowa

04:22 PM
Now
Cloudy Weather
99° F
Feels Like 106°
Precipitation 40 %
Wind 7 mph
UV Index (0 - 11+) 5
Humidity 39 %
Today
Sunny with a Chance of Thunderstorms
Day 99°
Night 64°
Precipitation 49 %
Wind 9 mph
UV Index (0 - 11+) 10

Warning: High UV Index Today: 10

High risk of harm from unprotected sun exposure. Take precautions: wear a hat, sunglasses, and apply sunscreen regularly if you’ll be outdoors for extended periods.

Sioux City Weather Forecast Updated

5 minutes ago
Last updated on

Air Quality in Sioux City

NOW
36 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 2.17 µg/m³
PM10 2.5 µg/m³
O3 0.039 ppm
NO2 0.2 ppb
SO2 0 ppb
CO 0.08 ppm
NH3 1.01 µg/m³
NO 0.07 µg/m³
PM2.5 – 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)
PM2.52.17 µg/m³
PM102.5 µg/m³
O376.58 µg/m³
NO20.32 µg/m³
SO20.06 µg/m³
CO85.96 µg/m³
NH31.01 µg/m³
NO0.07 µg/m³

Weather Alerts and Warnings for Sioux City

Severe Expected Likely

Extreme Heat Warning

Extreme Heat Warning issued July 20 at 8:00AM CDT until July 20 at 8:00PM CDT by NWS Sioux Falls SD
Jul 20, 11:00 AM Jul 20, 8:00 PM
WHAT: Dangerously hot conditions with heat index values up to 107
expected.

WHERE: Portions of northwest and west central Iowa, northeast
Nebraska, and southeast South Dakota.

WHEN: From 11 AM this morning to 8 PM CDT this evening.

IMPACTS: Heat related illnesses increase significantly during
extreme heat and high humidity events.
+ Read More
Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. Do not leave young children and pets in unattended vehicles. Car interiors will reach lethal temperatures in a matter of minutes. Take extra precautions when outside. Wear lightweight and loose fitting clothing. Try to limit strenuous activities to early morning or evening. Take action when you see symptoms of heat exhaustion and heat stroke. To reduce risk during outdoor work, the Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air conditioned environments. Anyone overcome by heat should be moved to a cool and shaded location. Heat stroke is an emergency! Call 9 1 1.
Updated: Jul 20, 4:17 PM Source: NWS Alert
Moderate Expected Likely

Heat Advisory

Heat Advisory issued July 19 at 8:56PM CDT until July 20 at 8:00PM CDT by NWS Sioux Falls SD
Jul 20, 12:00 PM Jul 20, 8:00 PM
WHAT: Heat index values up to 105 expected.

WHERE: Portions of northwest and west central Iowa, northeast
Nebraska, and southeast South Dakota.

WHEN: From noon to 8 PM CDT Monday.

IMPACTS: Hot temperatures and high humidity may cause heat
illnesses.
+ Read More
Do not leave young children and pets in unattended vehicles. Car interiors will reach lethal temperatures in a matter of minutes. Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. To reduce risk during outdoor work, the Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air conditioned environments. Anyone overcome by heat should be moved to a cool and shaded location. Heat stroke is an emergency! Call 9 1 1.
Updated: Jul 19, 11:46 PM Source: NWS Alert