Arco, ID Weather

Butte County8:52 AM MDT43.64°N, 113.30°WElevation 5,325 ft

Current conditions

Cloudy
45°
Cloudy
Feels like 40°
High 64°·Low 42°
WindW 8 mph
Humidity93%
Dew point43°
Pressure30.20 inHg
Visibility10.0 mi
Cloud cover69%
UV index0 Low
Sunrise7:55 AM
Sunset6:42 PM

Observed at Hailey, Friedman Memorial Airport · 1 hr ago

Forecast

10-day

  • Today

    A chance of rain before 10am. Mostly sunny, with a high near 64. East southeast wind 3 to 8 mph. Chance of precipitation is 30%.

  • Tonight

    A slight chance of rain between midnight and 3am. Partly cloudy. Low around 42, with temperatures rising to around 44 overnight. East wind around 6 mph. Chance of precipitation is 20%.

  • Thursday

    A slight chance of rain between 11am and noon, then showers and thunderstorms likely. Partly sunny. High near 62, with temperatures falling to around 60 in the afternoon. East wind 5 to 8 mph. Chance of precipitation is 60%.

National Weather Service forecast updated 3 hrs ago.

Hourly

Hourly forecast
  1. Now Slight Chance Light Rain 41°20%
  2. 9 AM Slight Chance Light Rain 45°19%
  3. 10 AM Mostly Sunny 50°
  4. 11 AM Mostly Sunny 53°
  5. 12 PM Mostly Sunny 56°
  6. 1 PM Mostly Sunny 60°
  7. 2 PM Sunny 62°
  8. 3 PM Sunny 63°
  9. 4 PM Sunny 63°
  10. 5 PM Sunny 64°
  11. 6 PM Mostly Clear 62°10%
  12. 7 PM Partly Cloudy 59°
  13. 8 PM Partly Cloudy 56°
  14. 9 PM Mostly Clear 52°
  15. 10 PM Partly Cloudy 50°
  16. 11 PM Partly Cloudy 48°11%
  17. Thu12 AM Slight Chance Light Rain 48°21%
  18. 1 AM Slight Chance Light Rain 47°18%
  19. 2 AM Slight Chance Light Rain 47°15%
  20. 3 AM Partly Cloudy 46°12%
  21. 4 AM Partly Cloudy 45°13%
  22. 5 AM Partly Cloudy 44°
  23. 6 AM Mostly Sunny 44°
  24. 7 AM Mostly Sunny 43°

Daily forecast

Details
  1. TodayOct 21 Chance Light Rain then Mostly Sunny Chance Light Rain then Mostly Sunny33%42°64°
  2. ThuOct 22 Slight Chance Light Rain then Showers And Thunderstorms Likely Slight Chance Light Rain then Showers And Thunderstorms Likely99%40°62°
  3. FriOct 23 Rain Rain93%30°49°
  4. SatOct 24 Mostly Sunny Mostly Sunny30°48°
  5. SunOct 25 Sunny Sunny32°51°
  6. MonOct 26 Sunny Sunny11%31°52°
  7. TueOct 27 Sunny Sunny30°51°
  8. WedOct 28 Partly cloudy Partly cloudy37°54°
  9. ThuOct 29 Cloudy Cloudy38°55°

Days after the National Weather Service's seven are MET Norway's outlook, a computer model with no forecaster's review.

Radar

Full map
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Weather news near Arco

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Air quality

28
Good
Ozone

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

Craters of the Moon National Monument, ID reporting area · 1 hr ago. Data from AirNow (EPA and its state, local and tribal partners); preliminary and subject to change.

Sun & moon

Sunrise 7:55 AM
Sunset 6:42 PM
Daylight 10 h 46 min (−2 min 50 s tomorrow)
Waxing Gibbous · 78% lit
Moonrise 4:31 PM Moonset 2:53 AM
Full moon Oct 26 New moon Nov 9

Almanac

Monthly
Normal high / low57° / 28°
Record high79° (2003)
Record low10° (1987)
Wettest0.16 in (1943)
Month to date0.90 in (normal 0.44 in)

Howe, records since 1914. Normals 1991–2020. Data from NOAA's Regional Climate Centers (ACIS).

Forecasters' discussion

From the National Weather Service office in PIH, issued 7 hrs ago

Key Messages

- Mild temperatures through Thursday.

- Isolated showers and storms Today.

- Widespread rain arrives late Thursday.

- Much colder Friday.

Discussion

Issued at 111 AM MDT Wed Oct 21 2026

Low pressure off the coast of central California will remain in place today. It will start moving inland on Thursday, passing overhead Friday, before exiting the region on Saturday. Models show a batch of showers lifting northward through our area this morning but then clearing out for the afternoon with a few isolated showers developing late. We will probably see another wave of light showers Wednesday night into Thursday morning. But the main batch of precipitation will hold off until Thursday afternoon and evening. Models show a healthy band of showers and thunderstorms on the east side of the low as it moves northward. This is what will likely produce most of the precipitation over our area. There is also a good area of stratiform deformation zone rain on the north and northwest side of the low that will mainly pass through the central mountains into the Island Park region. Models are showing a good bit of dry air in the interior part of the low which could influence rainfall amounts. Forecast rainfall amounts remain relatively unchanged. The mean and 50th percentile qpf from the NBM shows 1.00 to 1.50 inches for east Idaho and across the Arco Desert into the Wood River and Lost River areas. The Magic Valley and central mountains look drier with around 0.50 inches. The 10th percentile is as low as 0.10 inches for the Magic Valley with 0.25 to 0.60 inches elsewhere. The 90th percentile is especially wet with amounts ranging from 1.25 inches to 2.00 inches. Both the operational GFS and NAM show this drier air in the reflectivity fields so the 90th percentile looks highly unlikely. But a drier than advertised system looks more plausible based on the dry air we are seeing in the models. The WPC forecast is just a tad under the 50% percentile. Snowfall with this system continues to look mostly unimpactful. Perhaps snow levels fall to some of our higher passes Friday night as the colder air settles into the area before the precipitation exits.

Cooler and drier air arrives for the weekend. We will notice about a 20 degree drop in temperatures from our highs on Thursday to highs for Friday. Temps will rebound slightly for next week, but remaining near or slightly below normal.

Aviation

Issued at 111 AM MDT Wed Oct 21 2026

A few showers may encroach upon terminals this morning. But conditions should remain vfr. Relatively light winds expected throughout the day.

Fire Weather

Issued at 111 AM MDT Wed Oct 21 2026

A few spotty showers are expected today with little to no measurable rain. Wetting rains will likely hold off until late Thursday afternoon and Thursday night.

Forecasts, observations and alerts in the United States come from the National Weather Service (NOAA); radar from NOAA's Multi-Radar Multi-Sensor system; satellite imagery from NASA's Global Imagery Browse Services (GIBS) and NOAA's GOES satellites; the map from the U.S. Geological Survey's National Map; air quality from AirNow (EPA and its partners); hurricane information from the National Hurricane Center; climate normals and records from NOAA's Regional Climate Centers (ACIS). Forecasts outside the United States and the UV index: MET Norway (CC BY 4.0); observations outside the U.S.: airport reports via NOAA's Aviation Weather Center. Place names: GeoNames (CC BY 4.0). Data are copied on a schedule and may lag the sources; for warnings that affect your safety, follow your local National Weather Service office and emergency officials. Weather news is drawn from the 4Search index and reflects what the press published. Terms of use.