Hidden Valley Lake has warmer summer afternoons than 85% of U.S. towns
The coldest hours of a January night bottom out at 36° on average. Expect the heaviest rain or snow in January and the lightest in July. By January nights alone, it runs milder than 82% of U.S. towns. If you like long walks, April, May and October offer highs of 68–77°.
A year in Hidden Valley Lake at a glance
Each month’s typical high and low, and what it brings.
What stands out about Hidden Valley Lake’s climate
Compared with towns across the U.S., with Hidden Valley Lake’s place in California beside it.
What a year in Hidden Valley Lake feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 209 frost-free days a year
In half of years the last 32° night comes by April 10 and the first by November 6. Frost and day counts come from NOAA’s station at Clearlake 4 Se, CA, 9 miles from the town’s center, 260 ft higher.
The 2023 USDA map puts Hidden Valley Lake’s center in zone 9a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 22°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 40 inches of rain a year
January is the wettest month and July the driest. Rain falls on about 62 days a year. Snow is rare: about 0.3" in a normal year at Middletown, CA, so most winters see none.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Hidden Valley Lake
82% of the work is heating. Months averaging under 55° run from November through March.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Clearlake 4 Se, CA.
Living with Hidden Valley Lake’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
209 frost-free days in zone 9a. The last frost comes by Apr 10 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Nov 6.
Months with highs of 62–84° and lows of 40° or more: April, May and October. 15 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Hidden Valley Lake from natural hazards, river flooding is the largest share (51%); heat waves, cold waves, winter storms and ice storms together are 1%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Hidden Valley Lake and similar climates
TownRatings has no climate map of the towns around Hidden Valley Lake yet.
Climates most like Hidden Valley Lake’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Hidden Valley Lake, CA | 36° | 92° | 40" | 0.3" |
| Lugoff, SC | 33° | 92° | 43" | 0.4" |
| Thomson, GA | 35° | 91° | 46" | 0.5" |
| Anna, TX | 34° | 94° | 41" | 0.2" |
| Marvin, NC | 31° | 91° | 43" | 0.2" |
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
Warmer than it used to be
The last 30 years in Hidden Valley Lake averaged 1.3° warmer than the 1900s. The biggest change is in January (+2.2°).
A smaller shift than in 52% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Hidden Valley Lake compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Hidden Valley Lake’s place among California’s.
Hidden Valley Lake weather by month
Highs, lows and precipitation from NOAA’s grid at Hidden Valley Lake’s center; snow, wet days and snow on the ground from Middletown, CA. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 56° | 36° | 8.5" | 0.0" | 11 | 0 | 42° – 54° |
| February | 59° | 38° | 7.8" | 0.2" | 9 | 0 | 41° – 55° |
| March | 63° | 39° | 5.4" | 0.1" | 8 | 0 | 43° – 58° |
| April | 68° | 42° | 2.6" | 0.0" | 7 | 0 | 48° – 60° |
| May | 76° | 47° | 1.4" | 0.0" | 4 | 0 | 53° – 70° |
| June | 85° | 53° | 0.3" | 0.0" | 1 | 0 | 63° – 73° |
| July | 92° | 57° | 0.0" | 0.0" | 0 | 0 | 70° – 78° |
| August | 91° | 55° | 0.0" | 0.0" | 0 | 0 | 69° – 77° |
| September | 86° | 51° | 0.1" | 0.0" | 1 | 0 | 65° – 73° |
| October | 77° | 46° | 1.7" | 0.0" | 3 | 0 | 57° – 69° |
| November | 63° | 39° | 3.9" | 0.0" | 8 | 0 | 43° – 56° |
| December | 56° | 35° | 8.3" | 0.0" | 12 | 0 | 41° – 50° |
| Year | 73° | 45° | 40.1" | 0.3" | 62 | 0 |
How much a month can swing
A normal is an average. May swings the most: from 1991 to 2020 its average ranged from 53° to 70°. July is the most reliable, staying within 8°.
Where Hidden Valley Lake’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Hidden Valley Lake’s center.
- Snow: Middletown, CA.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Clearlake 4 Se, CA, 9 miles from the town’s center, 260 ft higher; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Hidden Valley Lake’s climate
What is the weather like in Hidden Valley Lake?
A typical July afternoon reaches 92°, a January night drops to 36°, and snow is almost unheard of. Milder January nights than 82% of U.S. towns; hotter July afternoons than 85% of U.S. towns.
How cold does it get in Hidden Valley Lake in winter?
December nights average 35°. About 72 nights a year reach 32° or below. In the coldest December of the last 30 years the month averaged 41°.
How much snow does Hidden Valley Lake get?
About 0.3 inches in a normal winter at Middletown, CA, so most winters see none.
How hot does it get in Hidden Valley Lake?
July, with a typical high of 92° and a low of 57°. About 66 days a year reach 90° and 10 reach 100° (Clearlake 4 Se, CA).
When is the first and last frost in Hidden Valley Lake?
In half of years the last spring frost (32°) comes by April 10 and the first fall frost by November 6, about 209 frost-free days, at Clearlake 4 Se, CA.
What growing zone is Hidden Valley Lake in?
Zone 9a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 22°.
What is the best time of year to visit Hidden Valley Lake?
By one simple rule (highs of 62–84° and lows of 40° or more), April, May and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Hidden Valley Lake getting warmer?
Yes: 1991–2020 averaged 1.3° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 52% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Hidden Valley Lake.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.