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Lake Koocanusa is one of the reservoirs LakeRadar tracks in Montana. Fish documented in the area include Rainbow Trout and Kokanee Salmon. At around 46,700 acres (about 73 square miles), it is a large waterbody. A nearby water gauge supplies level and temperature readings where available. Below you will find an hourly and 7-day forecast, wind and gust outlook, water readings, fishing conditions, and activity scores for boating, paddling, and swimming. Nearby alternatives include Lake Koocanusa and Bowman Lake. Check the hourly forecast and activity outlook below before heading out to Lake Koocanusa.
Updated
No active alerts for this lake as of the last check (Oct 9, 4:39 AM MDT). Alerts are re-checked automatically; see the official source for updates.
Overall Good (84/100) across 4 activities. Best right now: Sailing (87/100).
How the score is calculated →Best good fishing window, averaging 88/100 across these hours. Wind 9 mph from the southwest. Dawn hours (07:00 local). Derived from the hourly forecast; official alerts are not forecast and are checked separately.
| Metric | 10a | 11a | 12p | 1p | 2p | 3p | 4p | 5p | 6p | 7p | 8p | 9p | 10p | 11p | 12a | 1a | 2a | 3a | 4a | 5a | 6a | 7a | 8a | 9a |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Temp (°F) | 49° | 49° | 48° | 47° | 47° | 48° | 53° | 55° | 56° | 58° | 57° | 56° | 55° | 52° | 50° | 48° | 47° | 46° | 45° | 45° | 44° | 43° | 43° | 42° |
| Wind (kts) | 8 | 8 | 8 | 8 | 9 | 10 | 10 | 10 | 13 | 13 | 13 | 14 | 14 | 14 | 13 | 11 | 10 | 12 | 12 | 12 | 7 | 7 | 7 | 4 |
| Direction | SW | SW | SW | SW | SW | SW | SW | SW | SW | SW | SW | W | W | W | SW | SW | W | SW | SW | SW | SW | SW | SW | W |
| Gusts (kts) | 17 | 17 | 17 | 19 | 20 | 21 | 24 | 26 | 27 | 30 | 31 | 27 | 27 | 27 | 26 | 26 | 26 | 22 | 21 | 18 | 13 | 12 | 10 | 8 |
| Precip % | 0% | 0% | 1% | 1% | 1% | 1% | 1% | 1% | 5% | 6% | 25% | 21% | 15% | 12% | 27% | 37% | 25% | 20% | 18% | 14% | 6% | 2% | 1% | 3% |
| Time | Temp | Wind | Gusts | Precip | Cloud | Condition |
|---|---|---|---|---|---|---|
| Fri, 4 AM MDT | 49°F | 9 mph SW (225°) | 20 mph | 0% | 79% | Mostly Cloudy |
| Fri, 5 AM MDT | 49°F | 9 mph SW (225°) | 20 mph | 0% | 73% | Mostly Cloudy |
| Fri, 6 AM MDT | 48°F | 9 mph SW (225°) | 20 mph | 1% | 60% | Partly Sunny |
| Fri, 7 AM MDT | 47°F | 9 mph SW (225°) | 22 mph | 1% | 52% | Partly Sunny |
| Fri, 8 AM MDT | 47°F | 10 mph SW (225°) | 23 mph | 1% | 47% | Mostly Sunny |
| Fri, 9 AM MDT | 48°F | 12 mph SSW (203°) | 24 mph | 1% | 24% | Sunny |
| Fri, 10 AM MDT | 53°F | 12 mph SSW (203°) | 28 mph | 1% | 16% | Sunny |
| Fri, 11 AM MDT | 55°F | 12 mph SSW (203°) | 30 mph | 1% | 30% | Mostly Sunny |
| Fri, 12 PM MDT | 56°F | 15 mph SW (225°) | 31 mph | 5% | 33% | Mostly Sunny |
| Fri, 1 PM MDT | 58°F | 15 mph SW (225°) | 35 mph | 6% | 47% | Mostly Sunny |
| Fri, 2 PM MDT | 57°F | 15 mph SW (225°) | 36 mph | 25% | 60% | Chance Light Rain |
| Fri, 3 PM MDT | 56°F | 16 mph WSW (248°) | 31 mph | 21% | 58% | Slight Chance Light Rain |
| Fri, 4 PM MDT | 55°F | 16 mph WSW (248°) | 31 mph | 15% | 62% | Slight Chance Light Rain |
| Fri, 5 PM MDT | 52°F | 16 mph WSW (248°) | 31 mph | 12% | 71% | Mostly Cloudy |
| Fri, 6 PM MDT | 50°F | 15 mph SW (225°) | 30 mph | 27% | 76% | Chance Light Rain |
| Fri, 7 PM MDT | 48°F | 13 mph SW (225°) | 30 mph | 37% | 73% | Chance Light Rain |
| Fri, 8 PM MDT | 47°F | 12 mph WSW (248°) | 30 mph | 25% | 72% | Chance Light Rain |
| Fri, 9 PM MDT | 46°F | 14 mph SW (225°) | 25 mph | 20% | 62% | Slight Chance Light Rain |
| Fri, 10 PM MDT | 45°F | 14 mph SW (225°) | 24 mph | 18% | 58% | Slight Chance Light Rain |
| Fri, 11 PM MDT | 45°F | 14 mph SW (225°) | 21 mph | 14% | 57% | Mostly Cloudy |
| Sat, 12 AM MDT | 44°F | 8 mph SW (225°) | 15 mph | 6% | 58% | Mostly Cloudy |
| Sat, 1 AM MDT | 43°F | 8 mph SW (225°) | 14 mph | 2% | 60% | Mostly Cloudy |
| Sat, 2 AM MDT | 43°F | 8 mph SW (225°) | 12 mph | 1% | 55% | Mostly Cloudy |
| Sat, 3 AM MDT | 42°F | 5 mph W (270°) | 9 mph | 3% | 47% | Partly Cloudy |
| Sat, 4 AM MDT | 41°F | 3 mph W (270°) | 8 mph | 5% | 58% | Mostly 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 | Overnight October 9, 2026 | Friday October 9, 2026 | Friday Night October 9, 2026 | Saturday October 10, 2026 | Saturday Night 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Temp (°F) | 46° | 58° | 38° | 41° | 30° | 35° | 26° | 45° | 31° | 49° | 34° | 46° | 35° | 48° |
| Wind | SW 9 mph | SW 9 to 16 mph | WSW 3 to 15 mph | NE 6 to 17 mph | NE 16 to 20 mph | NE 9 to 14 mph | NNE 6 to 9 mph | NNE 3 mph | SW 3 mph | WSW 5 mph | SW 3 to 7 mph | WSW 6 mph | WNW 5 mph | N 3 mph |
| Gusts | 20 mph | 36 mph | 30 mph | 27 mph | 38 mph | 31 mph | 18 mph | 8 mph | 6 mph | 7 mph | 12 mph | 10 mph | 9 mph | 7 mph |
| Precip % | 0% | 25% | 37% | 75% | 11% | 21% | 2% | 2% | 2% | 0% | 6% | 36% | 36% | 9% |
| Forecast |
No active USGS or USACE telemetry gauge is currently mapped to Lake Koocanusa. Not available from a verified source for this lake.
Good for fishing (83/100), from 5 available inputs. Supporting this: Wind 9 mph from the southwest. 0% chance of precipitation. 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 (84/100), from 4 available inputs. Supporting this: Wind 9 mph from the southwest. 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 (87/100), from 4 available inputs. Supporting this: Wind 9 mph from the SW 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 (82/100), from 5 available inputs. Supporting this: Wind 9 mph from the southwest. 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 MT Parks & Wildlife Authority. Public boaters should verify seasonal launch water levels, gate hours, and daily vehicle/vessel fees before traveling.
Providing high-quality outdoor access in MT, Lake Koocanusa accommodates powerboats, fishing craft, and paddleboards across its open waters. The lake is an essential community resource for water recreation and ecological conservation. Observe all posted navigation aids and safe boating distances while on the water.
Valid freshwater sport fishing license issued by Montana Fish, Wildlife & Parks (FWP) is required for anglers age 12+. 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, Kokanee 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 Lake Koocanusa 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 9, 4:39 AM MDT