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Arrowrock Reservoir is a reservoir in Idaho. Fish documented in the area include Rainbow Trout, Smallmouth Bass, and Sockeye Salmon. The water surface spans about 3,100 acres, making it a mid-sized body of water. The page brings together an hourly and 7-day forecast, wind and gust outlook, fishing conditions, and activity scores for boating, paddling, and swimming. Nearby alternatives include Anderson Ranch Reservoir and C.J. Strike Reservoir. Current weather, wind, and activity conditions for Arrowrock Reservoir are updated throughout the day.
Updated
No active alerts for this lake as of the last check (Oct 10, 1:07 PM MDT). Alerts are re-checked automatically; see the official source for updates.
Overall Good (87/100) across 4 activities. Best right now: Boating (89/100).
How the score is calculated →Best excellent fishing window, averaging 91/100 across these hours. Wind 6 mph from the north-northwest. Dusk hours (19:00 local). Derived from the hourly forecast; official alerts are not forecast and are checked separately.
| Metric | 7p | 8p | 9p | 10p | 11p | 12a | 1a | 2a | 3a | 4a | 5a | 6a | 7a | 8a | 9a | 10a | 11a | 12p | 1p | 2p | 3p | 4p | 5p | 6p |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Temp (°F) | 58° | 58° | 59° | 58° | 58° | 56° | 54° | 50° | 50° | 49° | 48° | 46° | 45° | 44° | 43° | 41° | 39° | 38° | 37° | 36° | 37° | 38° | 41° | 46° |
| Wind (kts) | 7 | 8 | 7 | 7 | 6 | 6 | 5 | 4 | 4 | 4 | 4 | 3 | 2 | 2 | 2 | 2 | 2 | 2 | 3 | 3 | 4 | 4 | 4 | 3 |
| Direction | NW | NW | NW | NW | N | N | N | N | N | NW | NW | NW | NW | NW | W | W | W | W | W | W | W | W | W | W |
| Gusts (kts) | 13 | 14 | 14 | 13 | 13 | 12 | 10 | 9 | 8 | 8 | 8 | 7 | 6 | 5 | 5 | 5 | 5 | 5 | 6 | 6 | 8 | 8 | 8 | 7 |
| Precip % | 6% | 4% | 3% | 3% | 3% | 14% | 15% | 17% | 20% | 24% | 25% | 8% | 13% | 21% | 8% | 7% | 9% | 4% | 4% | 4% | 3% | 3% | 12% | 11% |
| Time | Temp | Wind | Gusts | Precip | Cloud | Condition |
|---|---|---|---|---|---|---|
| Sat, 1 PM MDT | 58°F | 8 mph WNW (293°) | 15 mph | 6% | 48% | Mostly Sunny |
| Sat, 2 PM MDT | 58°F | 9 mph WNW (293°) | 16 mph | 4% | 57% | Partly Sunny |
| Sat, 3 PM MDT | 59°F | 8 mph WNW (293°) | 16 mph | 3% | 63% | Partly Sunny |
| Sat, 4 PM MDT | 58°F | 8 mph NW (315°) | 15 mph | 3% | 69% | Partly Sunny |
| Sat, 5 PM MDT | 58°F | 7 mph NNW (338°) | 15 mph | 3% | 67% | Partly Sunny |
| Sat, 6 PM MDT | 56°F | 7 mph NNW (338°) | 14 mph | 14% | 66% | Mostly Cloudy |
| Sat, 7 PM MDT | 54°F | 6 mph NNW (338°) | 12 mph | 15% | 71% | Slight Chance Rain Showers |
| Sat, 8 PM MDT | 50°F | 5 mph NNW (338°) | 10 mph | 17% | 48% | Slight Chance Rain Showers |
| Sat, 9 PM MDT | 50°F | 5 mph NNW (338°) | 9 mph | 20% | 49% | Slight Chance Rain Showers |
| Sat, 10 PM MDT | 49°F | 5 mph NW (315°) | 9 mph | 24% | 57% | Slight Chance Rain Showers |
| Sat, 11 PM MDT | 48°F | 5 mph NW (315°) | 9 mph | 25% | 67% | Chance Rain Showers |
| Sun, 12 AM MDT | 46°F | 3 mph NW (315°) | 8 mph | 8% | 68% | Mostly Cloudy |
| Sun, 1 AM MDT | 45°F | 2 mph NW (315°) | 7 mph | 13% | 71% | Mostly Cloudy |
| Sun, 2 AM MDT | 44°F | 2 mph WNW (293°) | 6 mph | 21% | 62% | Slight Chance Rain Showers |
| Sun, 3 AM MDT | 43°F | 2 mph W (270°) | 6 mph | 8% | 60% | Mostly Cloudy |
| Sun, 4 AM MDT | 41°F | 2 mph W (270°) | 6 mph | 7% | 58% | Mostly Cloudy |
| Sun, 5 AM MDT | 39°F | 2 mph W (270°) | 6 mph | 9% | 73% | Mostly Cloudy |
| Sun, 6 AM MDT | 38°F | 2 mph W (270°) | 6 mph | 4% | 69% | Partly Sunny |
| Sun, 7 AM MDT | 37°F | 3 mph W (270°) | 7 mph | 4% | 65% | Partly Sunny |
| Sun, 8 AM MDT | 36°F | 3 mph W (270°) | 7 mph | 4% | 54% | Partly Sunny |
| Sun, 9 AM MDT | 37°F | 5 mph W (270°) | 9 mph | 3% | 51% | Partly Sunny |
| Sun, 10 AM MDT | 38°F | 5 mph W (270°) | 9 mph | 3% | 45% | Mostly Sunny |
| Sun, 11 AM MDT | 41°F | 5 mph W (270°) | 9 mph | 12% | 65% | Partly Sunny |
| Sun, 12 PM MDT | 46°F | 3 mph WSW (248°) | 8 mph | 11% | 64% | Partly Sunny |
| Sun, 1 PM MDT | 49°F | 3 mph WSW (248°) | 9 mph | 10% | 92% | Cloudy |
Official National Weather Service hourly forecast. Showing 10 of 25 hours. Wind arrows point the way the wind is blowing; the compass point and degrees show where it comes from.
| Period | This Afternoon October 10, 2026 | Tonight October 10, 2026 | Sunday October 11, 2026 | Sunday Night October 11, 2026 | Columbus Day October 12, 2026 | Monday Night October 12, 2026 | Tuesday October 13, 2026 | Tuesday Night October 13, 2026 | Wednesday October 14, 2026 | Wednesday Night October 14, 2026 | Thursday October 15, 2026 | Thursday Night October 15, 2026 | Friday October 16, 2026 | Friday Night October 16, 2026 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Temp (°F) | 60° | 36° | 52° | 34° | 50° | 33° | 57° | 34° | 61° | 35° | 64° | 37° | 69° | 41° |
| Wind | NW 9 mph | WNW 2 to 7 mph | W 5 mph | WNW 5 mph | WNW 5 mph | NNW 0 to 3 mph | WNW 2 to 7 mph | NNW 1 to 6 mph | NNW 2 to 7 mph | NNW 5 mph | N 2 to 6 mph | N 2 mph | ESE 5 mph | ESE 5 mph |
| Gusts | 16 mph | 14 mph | 12 mph | 10 mph | 9 mph | 9 mph | 14 mph | 14 mph | 15 mph | 13 mph | 10 mph | 8 mph | 10 mph | 9 mph |
| Precip % | 6% | 25% | 44% | 64% | 34% | 4% | 2% | 1% | 1% | 0% | 0% | 0% | 0% | 0% |
| Forecast |
Nearby river temperature: 56.8°F at SF BOISE RIVER AT NEAL BRIDGE NR ARROWROCK DAM ID (14.1 mi away) · Oct 10, 6:45 PM UTC
Good for fishing (84/100), from 5 available inputs. Supporting this: Wind 8 mph from the west-northwest. Sky is mostly cloudy (48% cloud cover). Not available from a verified source for this lake: pressure trend, water temperature. Confidence is moderate (74%) because some inputs are unavailable or older than ideal.
Good for boating (89/100), from 4 available inputs. Supporting this: Wind 8 mph from the west-northwest. No active official alerts for this lake. Not available from a verified source for this lake: visibility and conditions, verified water access. Confidence is moderate (84%) because some inputs are unavailable or older than ideal.
Good for sailing (89/100), from 4 available inputs. Supporting this: Wind 8 mph from the WNW is in the preferred sailing range. No active official alerts for this lake. Not available from a verified source for this lake: visibility. Confidence is high (88%).
Good for kayaking (88/100), from 5 available inputs. Supporting this: Wind 8 mph from the west-northwest. No active official alerts for this lake. Confidence is high (90%).
Water temperature is not available from a verified source for this lake. No swimming score is shown without it.
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Individual boat ramp GPS coordinates are maintained under the jurisdiction of ID Parks & Wildlife Authority. Public boaters should verify seasonal launch water levels, gate hours, and daily vehicle/vessel fees before traveling.
Arrowrock Reservoir is an important freshwater reservoir in ID, overseen by state and local natural resource agencies to balance public recreation with natural resource stewardship. The waterbody offers excellent conditions for sport fishing, cruising, and paddling during favorable weather windows. Checking real-time water levels and ramp clearances ensures safe navigation along the shoreline.
Valid freshwater sport fishing license issued by Idaho Department of Fish and Game (IDFG) is required for anglers age 14+. Digital license on mobile is accepted.
Mandatory Clean, Drain & Dry inspection. Out-of-area craft require on-site Aquatic Invasive Species (AIS Quagga/Zebra) inspection or decontamination before launch. USCG life jackets required for all.
Public shoreline and boating access managed by State & Local Authorities. Verify seasonal gate hours, launch fees, and parking rules before travel.
High-speed motorboating, pontoon cruising, wakeboarding, and water skiing across main channels. Target gamefish include Rainbow Trout, Smallmouth Bass, Sockeye Salmon. Morning hours typically provide optimal glassy conditions for kayak and stand-up paddleboard (SUP) touring.
Warm water temperatures, peak swimming, active watersports, and open full-service campgrounds. Highest weekly attendance; plan early arrivals on summer weekends.
Spring pre-spawn and fall feeding transitions create prime trophy angling conditions. Cooler air, lower boat traffic, and vibrant seasonal shoreline foliage.
Northern cold winter conditions with freezing air temperatures and potential surface ice formation. Ramps and water systems may be winterized. Confirm open status before visiting.
No external source rows are cited by the data currently shown on this page.
Updated
Scores are heuristics, not safety guarantees. LakeRadar scores summarize available conditions and are not a substitute for official warnings, local rules, or on-water judgment.
All telemetry for Arrowrock Reservoir is synchronized directly from authorized federal and state monitoring networks (USGS, NWS, NOAA, and state environmental authorities). Observations are strictly instrumented readings — unmonitored sensors are transparently disclosed rather than synthetic estimates.
Last source audit: Oct 10, 1:07 PM MDT