Harriman State Park, ID

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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:

🌤
43°F
High: 57° | Low: 29°
Current Temperature
Station: IPFI1
Observed at: 10:54 am CST on 11/12/26
Wind: 2 mph | Humidity: 68%
Today:Mostly sunny. High near 57, with temperatures falling to around 48 in the afternoon. Southeast wind around 2 mph.
Tonight:Mostly cloudy. Low around 29, with temperatures rising to around 31 overnight. Northeast wind around 3 mph.
Friday:Mostly cloudy. High near 53, with temperatures falling to around 47 in the afternoon. South southeast wind 1 to 6 mph, with gusts as high as 18 mph.
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Today’s Report:

🥾 Hiking

Excellent
  92 /100

Excellent for hiking. High near 53°F. Low rain risk (1%). Light wind (6 mph).

  • Temp: Marginal weather factor
  • Rain: Favorable conditions
  • Wind: Favorable conditions
  • Thunderstorm: Favorable conditions
Tomorrow's Outlook:
Not Recommended 3/100
Not Recommended for hiking. High near 35°F. High rain probability (75%). Temperatures outside comfort limits (35°F).

⛺ Camping

Excellent
  100 /100

Excellent for camping. High near 53°F. Low rain risk (1%). Light wind (6 mph).

  • Temp: Favorable conditions
  • Rain: Favorable conditions
  • Wind: Favorable conditions
  • Thunderstorm: Favorable conditions
Tomorrow's Outlook:
Not Recommended 3/100
Not Recommended for camping. High near 35°F. High rain probability (75%). Temperatures outside comfort limits (35°F).

🛶 Paddling

Not Recommended
  23 /100

Not Recommended for paddling. High near 53°F. Low rain risk (1%). Light wind (6 mph). Temperatures outside comfort limits (53°F).

  • Temp: Unfavorable weather factor
  • Rain: Favorable conditions
  • Wind: Favorable conditions
  • Thunderstorm: Favorable conditions
Tomorrow's Outlook:
Not Recommended 4/100
Not Recommended for paddling. High near 35°F. High rain probability (75%). Temperatures outside comfort limits (35°F).

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

🌤
43°F
High: 57° | Low: 29°
Current Temperature
Station: IPFI1
Observed at: 10:54 am CST on 11/12/26
Wind: 2 mph | Humidity: 68%
Thu ⛅
57° 29°
0%
Fri ☁
53° 31°
1%
Sat ❄
41° 27°
75%
Sun ⛅
43° 25°
2%
Mon 🌧
48° 28°
29%
Tue ❄
44° 27°
56%
Wed ❄
40° 25°
62%

7-Day High Temperature Trend

57° Thu 53° Fri 41° Sat 43° Sun 48° Mon 44° Tue 40° Wed

7-Day Low Temperature Trend

29° Thu 31° Fri 27° Sat 25° Sun 28° Mon 27° Tue 25° Wed

📊 7-Day Outdoor Outlook

Good Fair Poor 100 Thu 85 Fri 18 Sat 20 Sun 20 Mon 19 Tue 19 Wed
Forecast data from the National Weather Service  |  Last Updated: November 12, 2026 8:48 pm CST

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.