Today | Weather | Friday, September 18, 2026
Active Weather Warnings

Weather in Nampa, Idaho

07:48 PM
Now
Cloudy Night
70° F
Feels Like 66°
Precipitation 1 %
Wind 7 mph
Humidity 43 %
Today
Night
Day 73°
Night 55°
Precipitation 4 %
Wind 7 mph

Nampa Weather Forecast Updated

34 minutes ago
Last updated on
Weather Forecast History
Last Year's Weather on This Day (September 18, 2025)
Cloudy Night

Day

90°

Night

55°

Wind

5 mph

Precipitation

0 %

Air Quality in Nampa

NOW
45 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 1.44 µg/m³
PM10 2.05 µg/m³
O3 0.048 ppm
NO2 0.3 ppb
SO2 0 ppb
CO 0.09 ppm
NH3 0.34 µg/m³
NO 0 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)
PM2.51.44 µg/m³
PM102.05 µg/m³
O394.5 µg/m³
NO20.49 µg/m³
SO20.02 µg/m³
CO97.77 µg/m³
NH30.34 µg/m³
NO0 µg/m³

Weather Alerts and Warnings for Nampa

Severe Future Possible

Flash Flood Watch

Flash Flood Watch issued September 18 at 10:50AM MDT until September 19 at 12:00AM MDT by NWS Boise ID
Sep 18, 10:50 AM Sep 19, 12:00 AM
WHAT: Flash flooding and debris flows caused by excessive rainfall
are possible over the Wapiti, Crooked, Buckhorn burn scar areas.

WHERE: Portions of south central and southwest Idaho, including
the following areas, in south central Idaho, Western Magic Valley.
In southwest Idaho, Boise Mountains, Camas Prairie, Lower Treasure
Valley, Upper Treasure Valley and West Central Mountains.

WHEN: Through this evening.

IMPACTS: Heavy rainfall over the Wapiti, Crooked, Buckhorn burn
scar is expected up to and during the period of the watch.
Residents near the Wapiti, Crooked, Buckhorn burn scar should
prepare for potential debris flow. Be sure to stay up to date with
information from local authorities. Heavy rainfall could trigger
flash flooding or debris flows in and near recent wildfire burn
scars.

ADDITIONAL DETAILS:
- National Weather Service Meteorologists are forecasting heavy
rainfall over the burn scar, which may lead to flash flooding and
debris flows.
- Some locations that may experience flash flooding include...
Idaho City, Fairfield, Lowman, Horseshoe Bend, Pine, Prairie,
Atlanta, Anderson Dam, Corral, Centerville, Pioneerville, Garden
Valley, Banks, Gardena, Crouch, Placerville, Trinity Lakes, Rocky
Bar, Dutch Creek Guard Station and Featherville.
- https://www.weather.gov/safety/flood
+ Read More
You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued.
Updated: Sep 18, 7:13 PM Source: NWS Alert