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Union Valley Reservoir is one of the reservoirs LakeRadar tracks in California. The water surface spans about 2,860 acres, making it a mid-sized body of water. Other waters in the region include Caples Lake, Lake Tahoe, and Donner Lake. Below you will find an hourly and 7-day forecast, wind and gust outlook, and activity scores for boating, paddling, and swimming. This page combines the live forecast, wind, and conditions for Union Valley Reservoir so you can plan a visit.
Updated
No active alerts for this lake as of the last check (Oct 9, 1:07 AM PDT). Alerts are re-checked automatically; see the official source for updates.
Best good fishing window, averaging 86/100 across these hours. Wind 5 mph from the west-southwest. Measured water temperature 52°F from a representative gauge 25.2 mi away. Provisional data. Derived from the hourly forecast; official alerts are not forecast and are checked separately.
| Metric | 8a | 9a | 10a | 11a | 12p | 1p | 2p | 3p | 4p | 5p | 6p | 7p | 8p | 9p | 10p | 11p | 12a | 1a | 2a | 3a | 4a | 5a | 6a | 7a |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Temp (°F) | 57° | 57° | 57° | 56° | 57° | 56° | 55° | 56° | 60° | 67° | 74° | 77° | 78° | 77° | 78° | 77° | 75° | 73° | 64° | 59° | 58° | 57° | 57° | 56° |
| Wind (kts) | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 3 | 2 | 2 | 3 | 5 | 6 | 6 | 7 | 6 | 6 | 4 | 2 | 3 | 4 | 2 | 2 | 1 |
| Direction | E | E | E | E | E | E | E | E | SE | S | SW | SW | SW | SW | SW | W | W | W | SW | S | SE | SE | SE | SE |
| Gusts (kts) | 5 | 5 | 5 | 4 | 4 | 5 | 5 | 7 | 7 | 7 | 9 | 12 | 15 | 16 | 16 | 15 | 13 | 8 | 5 | 6 | 8 | 5 | 5 | 4 |
| Precip % | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 1% | 1% | 1% | 0% | 2% | 1% | 1% | 2% | 3% | 3% | 3% | 3% |
| Time | Temp | Wind | Gusts | Precip | Cloud | Condition |
|---|---|---|---|---|---|---|
| Fri, 1 AM PDT | 57°F | 2 mph ENE (68°) | 6 mph | 0% | 11% | Mostly Clear |
| Fri, 2 AM PDT | 57°F | 2 mph E (90°) | 6 mph | 0% | 11% | Mostly Clear |
| Fri, 3 AM PDT | 57°F | 2 mph E (90°) | 6 mph | 0% | 10% | Mostly Clear |
| Fri, 4 AM PDT | 56°F | 2 mph E (90°) | 5 mph | 0% | 27% | Partly Cloudy |
| Fri, 5 AM PDT | 57°F | 2 mph E (90°) | 5 mph | 0% | 11% | Mostly Clear |
| Fri, 6 AM PDT | 56°F | 2 mph ENE (68°) | 6 mph | 0% | 10% | Sunny |
| Fri, 7 AM PDT | 55°F | 2 mph E (90°) | 6 mph | 0% | 4% | Sunny |
| Fri, 8 AM PDT | 56°F | 3 mph E (90°) | 8 mph | 0% | 2% | Sunny |
| Fri, 9 AM PDT | 60°F | 2 mph ESE (113°) | 8 mph | 0% | 1% | Sunny |
| Fri, 10 AM PDT | 67°F | 2 mph S (180°) | 8 mph | 0% | 1% | Sunny |
| Fri, 11 AM PDT | 74°F | 3 mph SSW (203°) | 10 mph | 0% | 0% | Sunny |
| Fri, 12 PM PDT | 77°F | 6 mph SW (225°) | 14 mph | 0% | 1% | Sunny |
| Fri, 1 PM PDT | 78°F | 7 mph SW (225°) | 17 mph | 1% | 0% | Sunny |
| Fri, 2 PM PDT | 77°F | 7 mph SW (225°) | 18 mph | 1% | 1% | Sunny |
| Fri, 3 PM PDT | 78°F | 8 mph SW (225°) | 18 mph | 1% | 0% | Sunny |
| Fri, 4 PM PDT | 77°F | 7 mph WSW (248°) | 17 mph | 0% | 0% | Sunny |
| Fri, 5 PM PDT | 75°F | 7 mph WSW (248°) | 15 mph | 2% | 7% | Sunny |
| Fri, 6 PM PDT | 73°F | 5 mph WSW (248°) | 9 mph | 1% | 10% | Mostly Clear |
| Fri, 7 PM PDT | 64°F | 2 mph SSW (203°) | 6 mph | 1% | 27% | Partly Cloudy |
| Fri, 8 PM PDT | 59°F | 3 mph SSE (158°) | 7 mph | 2% | 24% | Mostly Clear |
| Fri, 9 PM PDT | 58°F | 5 mph SE (135°) | 9 mph | 3% | 6% | Mostly Clear |
| Fri, 10 PM PDT | 57°F | 2 mph ESE (113°) | 6 mph | 3% | 12% | Mostly Clear |
| Fri, 11 PM PDT | 57°F | 2 mph SE (135°) | 6 mph | 3% | 11% | Mostly Clear |
| Sat, 12 AM PDT | 56°F | 1 mph SE (135°) | 5 mph | 3% | 10% | Mostly Clear |
| Sat, 1 AM PDT | 55°F | 1 mph SSE (158°) | 5 mph | 3% | 8% | Mostly Clear |
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) | 54° | 79° | 50° | 65° | 40° | 54° | 35° | 48° | 33° | 56° | 36° | 64° | 43° | 70° |
| Wind | ENE 2 mph | S 2 to 8 mph | SSE 1 to 5 mph | SSW 2 to 12 mph | SSW 1 to 10 mph | SSW 1 to 8 mph | WNW 0 to 6 mph | W 0 to 3 mph | NNW 0 to 3 mph | N 0 to 5 mph | N 2 to 7 mph | WNW 1 to 5 mph | ENE 3 to 12 mph | NNE 2 to 9 mph |
| Gusts | 6 mph | 18 mph | 9 mph | 28 mph | 25 mph | 20 mph | 14 mph | 9 mph | 8 mph | 9 mph | 12 mph | 10 mph | 21 mph | 17 mph |
| Precip % | 0% | 2% | 4% | 0% | 6% | 32% | 71% | 71% | 28% | 6% | 3% | 1% | 0% | 0% |
| Forecast |
GENERAL C NR MEEKS BAY CA · Oct 9, 1:45 AM UTC
Good for fishing (88/100), from 6 available inputs. Supporting this: Wind 2 mph from the north-northwest. Dusk hours (19:00 local). Not available from a verified source for this lake: pressure trend. Confidence is moderate (82%) because some inputs are unavailable or older than ideal.
Excellent for boating (98/100), from 4 available inputs. Supporting this: Wind 2 mph from the north-northwest. Gusts to 6 mph. 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.
Fair for sailing (70/100), from 4 available inputs. Supporting this: Gusts are within 4 mph of sustained wind, so the breeze is steady. No active official alerts for this lake. Working against it: Wind 2 mph is light; expect limited sailing. Not available from a verified source for this lake: visibility. Confidence is high (88%).
Fair for kayaking (73/100), from 5 available inputs. Supporting this: Wind 2 mph from the north-northwest. Gusts to 6 mph. Water temperature is 52°F (combined air+water: 120°F). Cold shock hazard: sudden immersion below 55°F poses serious risk. Confidence is high (90%).
Surface water measured at 52°F. Cold shock reflex presents an immediate drowning risk.
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Individual boat ramp GPS coordinates are maintained under the jurisdiction of CA Parks & Wildlife Authority. Public boaters should verify seasonal launch water levels, gate hours, and daily vehicle/vessel fees before traveling.
Union Valley Reservoir provides vital open-water recreation for visitors across CA, offering public boat ramps and scenic shoreline amenities. Anglers target an assortment of freshwater species while pleasure boaters cruise its open basins. Facility operations and resource conservation are overseen by state and local natural resource agencies.
Valid freshwater sport fishing license issued by California Department of Fish and Wildlife (CDFW) is required for anglers age 16+. 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 Brook Trout, Green Sunfish, Rainbow Trout, Brown Trout. 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.
Mild year-round outdoor climate. Uncrowded waters, active winter bass and crappie fishing, and open year-round boat launch access.
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 Union Valley 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 9, 1:07 AM PDT