Harriman State Park

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Henry's Fork River from Last Chance, Island Park, Idaho
Henry's Fork River from Last Chance, Island Park, Idaho - Z3lvs, CC0, via Wikimedia Commons

Today’s Forecast:

🌤
79°F
Current Temperature
Station: IPFI1
Observed at: 4:54 pm
Wind: 4 mph | Humidity: 38%
⚠️
Air Quality Alert
Air Quality Alert issued July 27 at 10:23AM MDT by NWS Pocatello ID (Expires: July 28, 2026 4:00 pm)
Show Alert Details & Instructions
Description: AQAPIH * WHAT...Air Quality Advisory because of degraded air quality. Air Quality Index is forecast to be Unhealthy for Sensitive Groups. * WHERE...BONNEVILLE, BUTTE, CLARK, CUSTER, FREMONT, JEFFERSON, MADISON, AND TETON COUNTIES. * WHEN...THROUGH WEDNESDAY JULY 29TH. * IMPACTS...Members of sensitive groups may experience health effects. The general public is less likely to be affected. Instructions: Air pollutants can cause breathing difficulties for children, the elderly, as well as persons with respiratory problems. Those individuals who are sensitive to increased particulate matter or smoke are encouraged to avoid prolonged or strenuous outdoor activity during this advisory. Open burning is prohibited by air quality rule. It is also recommended that all other individuals limit prolonged or strenuous activity outdoors. THIS STATEMENT IS ISSUED BY THE IDAHO DEPARTMENT OF ENVIRONMENTAL QUALITY, AIR QUALITY GROUP. FOR MORE INFORMATION, CONTACT DEQ's Idaho Falls Regional Office at (208)528-2650.
⚠️
Air Quality Alert
Air Quality Alert issued July 27 at 9:00AM MDT by NWS Pocatello ID (Expires: July 28, 2026 2:00 pm)
Show Alert Details & Instructions
Description: AQAPIH * WHAT...Air Quality Advisory because of degraded air quality. Air Quality Index is forecast to be Unhealthy. * WHERE...CASSIA, LINCOLN, AND MINIDOKA COUNTIES. * WHEN...THROUGH WEDNESDAY JULY 29TH. * IMPACTS...Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Instructions: Air pollutants can cause breathing difficulties for children, the elderly, as well as persons with respiratory problems. Those individuals who are sensitive to increased particulate matter or smoke are encouraged to avoid prolonged or strenuous outdoor activity during this advisory. Open burning is prohibited by air quality rule. It is also recommended that all other individuals limit prolonged or strenuous activity outdoors. THIS STATEMENT IS ISSUED BY THE IDAHO DEPARTMENT OF ENVIRONMENTAL QUALITY, AIR QUALITY GROUP. FOR MORE INFORMATION, CONTACT DEQ's Twin Falls Regional Office at (208)736-2190.
⚠️
Air Quality Alert
Air Quality Alert issued July 27 at 8:52AM MDT by NWS Pocatello ID (Expires: July 28, 2026 12:00 pm)
Show Alert Details & Instructions
Description: AQAPIH * WHAT...Air Quality Advisory because of degraded air quality. Air Quality Index is forecast to be Unhealthy for Sensitive Groups. * WHERE...FOR POWER, BANNOCK, AND BINGHAM COUNTIES. * WHEN...THROUGH WEDNESDAY JULY 29TH. * IMPACTS...Members of sensitive groups may experience health effects. The general public is less likely to be affected. Instructions: Air pollutants can cause breathing difficulties for children, the elderly, as well as persons with respiratory problems. Those individuals who are sensitive to increased particulate matter or smoke are encouraged to avoid prolonged or strenuous outdoor activity during this advisory. Open burning is prohibited by air quality rule. It is also recommended that all other individuals limit prolonged or strenuous activity outdoors. THIS STATEMENT IS ISSUED BY THE IDAHO DEPARTMENT OF ENVIRONMENTAL QUALITY, AIR QUALITY GROUP. FOR MORE INFORMATION, CONTACT DEQ's Pocatello Regional Office at (208)236-6160.
⚠️
Air Quality Alert
Air Quality Alert issued July 27 at 8:42AM MDT by NWS Pocatello ID (Expires: July 28, 2026 4:00 pm)
Show Alert Details & Instructions
Description: AQAPIH * WHAT...Air Quality Advisory because of degraded air quality. Air Quality Index is forecast to be Unhealthy for Sensitive Groups. * WHERE...BONNEVILLE, BUTTE, CLARK, CUSTER, FREMONT, JEFFERSON, MADISON, AND TETON COUNTIES. * WHEN...THROUGH WEDNESDAY JULY 29TH. * IMPACTS...Members of sensitive groups may experience health effects. The general public is less likely to be affected. Instructions: Air pollutants can cause breathing difficulties for children, the elderly, as well as persons with respiratory problems. Those individuals who are sensitive to increased particulate matter or smoke are encouraged to avoid prolonged or strenuous outdoor activity during this advisory. Open burning is prohibited by air quality rule. It is also recommended that all other individuals limit prolonged or strenuous activity outdoors. THIS STATEMENT IS ISSUED BY THE IDAHO DEPARTMENT OF ENVIRONMENTAL QUALITY, AIR QUALITY GROUP. FOR MORE INFORMATION, CONTACT DEQ's Idaho Falls Regional Office at (208)528-2650.
This Afternoon:A slight chance of rain before 3pm, then a slight chance of showers and thunderstorms between 3pm and 4pm. Partly sunny, with a high near 84. South southwest wind around 7 mph. Chance of precipitation is 20%.
Tonight:Patchy smoke and a slight chance of showers and thunderstorms between 8pm and 9pm, then areas of smoke and a slight chance of rain between 9pm and midnight. Partly cloudy. Low around 52, with temperatures rising to around 54 overnight. Southeast wind 2 to 6 mph. Chance of precipitation is 20%.
Tuesday:Sunny, with a high near 87. South southwest wind 2 to 8 mph.

Today’s Report:

🥾 Hiking

Use Caution
  44 /100

Use Caution for hiking. High near 83°F. Low rain risk (19%). Light wind (7 mph). Slight chance of thunderstorms.

  • Temp: Marginal weather factor
  • Rain: Favorable conditions
  • Wind: Favorable conditions
  • Thunderstorm: Marginal weather factor
Tomorrow's Outlook:
Good 76/100
Good for hiking. High near 87°F. Low rain risk (5%). Light wind (8 mph).

⛺ Camping

Use Caution
  45 /100

Use Caution for camping. High near 83°F. Low rain risk (19%). Light wind (7 mph). Slight chance of thunderstorms.

  • Temp: Marginal weather factor
  • Rain: Favorable conditions
  • Wind: Favorable conditions
  • Thunderstorm: Marginal weather factor
Tomorrow's Outlook:
Good 82/100
Good for camping. High near 87°F. Low rain risk (5%). Light wind (8 mph).

🛶 Paddling

Use Caution
  48 /100

Use Caution for paddling. High near 83°F. Low rain risk (19%). Light wind (7 mph). Slight chance of thunderstorms.

  • Temp: Favorable conditions
  • Rain: Favorable conditions
  • Wind: Favorable conditions
  • Thunderstorm: Marginal weather factor
Tomorrow's Outlook:
Excellent 96/100
Excellent for paddling. High near 87°F. Low rain risk (5%). Light wind (8 mph).

About Harriman State Park

Harriman State Park is an Idaho destination for a premium Nordic state park with trails, river access, and year-round lodging.

Make the Most of a Harriman State Park Day

Match the route, launch, facility, or turnaround time to wind, precipitation, temperature, smoke, water, snow, road access, and daylight. Keep a shorter or more sheltered backup ready.

Weather Tips for Harriman State Park

  • Check official access notices, alerts, road or trail conditions, fire restrictions, and local forecasts before leaving.
  • Check river flow, reservoir wind, cold-water conditions, waves, lightning, and verified local ice reports before water plans; no forecast alone proves that ice is safe.
  • Carry layers, water, navigation, sun protection, and seasonal traction or flotation appropriate to the activity.
  • Allow extra time for remote roads, mountain passes, wildfire smoke, spring runoff, and limited winter daylight.

Nearby Towns and Areas

This page can also be useful when planning outdoor time near:

  • Island Park
  • Railroad Ranch
  • Last Chance
  • Mesa Falls
  • Big Springs

Plan Around the Conditions

Choose the safest version of a Harriman State Park day by matching the activity to current wind, precipitation, temperature, smoke, water or snow conditions, access, and daylight.

7-Day Forecast for Harriman State Park

🌤
79°F
Current Temperature
Station: IPFI1
Observed at: 4:54 pm
Wind: 4 mph | Humidity: 38%
Mon ⛈
84° 52°
16%
Tue ☀
87° 53°
5%
Wed ⛈
84° 51°
23%
Thu ☀
87° 52°
0%
Fri ☀
89° 53°
1%
Sat ☀
92° 55°
0%
Sun ☀
92° 51°
0%

7-Day High Temperature Trend

84° Mon 87° Tue 84° Wed 87° Thu 89° Fri 92° Sat 92° Sun

7-Day Low Temperature Trend

52° Mon 53° Tue 51° Wed 52° Thu 53° Fri 55° Sat 51° Sun

📊 7-Day Outdoor Outlook

Good Fair Poor 12 Mon 20 Tue 12 Wed 20 Thu 20 Fri 20 Sat 20 Sun
Forecast data from the National Weather Service  |  Last Updated: July 27, 2026 5:56 pm CDT

Weather by Season

Winter

Winter at Harriman State Park can bring snow, ice, wind, short daylight, and rapidly changing road or trail access. Confirm grooming, avalanche information, ice conditions, and facility operations for the listed winter activities.

Spring

Spring brings freeze-thaw mud, snowmelt, high rivers, cold water, and lingering mountain snow. Lower routes usually open well before high passes and backcountry trailheads.

Summer

Summer usually offers the broadest access, but dry heat, thunderstorms, lightning, wildfire smoke, fire restrictions, reservoir wind, and cold mountain water can alter plans.

Fall

Fall brings cooler air, shorter daylight, hunting-season awareness, and early snow at elevation. Confirm seasonal services and allow extra travel time on remote roads.

Key Climate Data Points

  • Annual average temperature: around 35–42°F, using the relevant local and elevation context.
  • Annual snowfall: commonly 80–150 inches, with a long snow season.
  • Warmest months: July and August are normally warmest.
  • Coolest months: December and January are typically coolest.
  • Wettest season: winter and spring usually provide the greatest mountain precipitation, with local variation.
  • Driest season: midsummer is generally driest, despite isolated thunderstorms.
  • Best outdoor window: June through October for warm-season access, with midwinter best at established winter destinations.