Potter Valley, California climate: Normal weather by month, frost dates and records
Potter Valley's normal year runs from 35°F December nights to 95°F July afternoons, with 45.0 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 15.1°C, December lows of 1°C, July highs of 35°C, 1,144 mm of precipitation a year.
- NOAA stationPotter Valley Powerhouse
- Station IDUSC00047109
- Location39.36°N 123.13°W
- Elevation1,018 ft (310 m)
- Population (census place)611
On October 14, the normal high in Potter Valley is 80°F and the normal low 44°F, and the chance of measurable rain or snow is 15%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Potter Valley.
- Jan 57° 35°
- Feb 61° 36°
- Mar 66° 39°
- Apr 71° 41°
- May 79° 45°
- Jun 87° 50°
- Jul 95° 54°
- Aug 94° 53°
- Sep 90° 49°
- Oct 79° 43°
- Nov 64° 38°
- Dec 56° 35°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Potter Valley each month?
July is the warmest month, with normal highs of 95°F; December the coldest, with normal lows of 35°F. The most precipitation falls in December (9.77 in), the least in July (0.04 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 57°F | 35°F | 46.1°F | 8.21 | 16 | <1 | 13 | 9 h 40 min |
| February | 61°F | 36°F | 48.9°F | 7.72 | 14 | <1 | 9 | 10 h 40 min |
| March | 66°F | 39°F | 52.4°F | 6.28 | 13 | <1 | 6 | 11 h 50 min |
| April | 71°F | 41°F | 55.8°F | 3.36 | 9 | 1 | 2 | 13 h 10 min |
| May | 79°F | 45°F | 62.0°F | 1.86 | 6 | 4 | <1 | 14 h 20 min |
| June | 87°F | 50°F | 68.4°F | 0.54 | 2 | 11 | <1 | 15 h |
| July | 95°F | 54°F | 74.7°F | 0.04 | <1 | 24 | <1 | 14 h 40 min |
| August | 94°F | 53°F | 73.4°F | 0.05 | 1 | 23 | <1 | 13 h 50 min |
| September | 90°F | 49°F | 69.5°F | 0.30 | 1 | 17 | <1 | 12 h 30 min |
| October | 79°F | 43°F | 61.1°F | 1.86 | 5 | 3 | 1 | 11 h 10 min |
| November | 64°F | 38°F | 51.2°F | 5.04 | 12 | <1 | 8 | 10 h |
| December | 56°F | 35°F | 45.3°F | 9.77 | 16 | <1 | 15 | 9 h 30 min |
| Year (annual) | 75°F | 43°F | 59.1°F | 45.03 | 96 | 82 | 54 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 14°C | 2°C | 7.8°C | 209 mm |
| February | 16°C | 2°C | 9.4°C | 196 mm |
| March | 19°C | 4°C | 11.3°C | 160 mm |
| April | 22°C | 5°C | 13.2°C | 85 mm |
| May | 26°C | 7°C | 16.7°C | 47 mm |
| June | 31°C | 10°C | 20.2°C | 14 mm |
| July | 35°C | 12°C | 23.7°C | 1 mm |
| August | 35°C | 12°C | 23.0°C | 1 mm |
| September | 32°C | 9°C | 20.8°C | 8 mm |
| October | 26°C | 6°C | 16.2°C | 47 mm |
| November | 18°C | 3°C | 10.7°C | 128 mm |
| December | 13°C | 1°C | 7.4°C | 248 mm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00047109; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Potter Valley?
Normal highs sit between 65°F and 85°F in March, April, May and October. Of those, October has the fewest days with rain (5).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00047109.
When is the last frost in Potter Valley?
In Potter Valley, the last spring frost (32°F) comes after April 8 in half of years and after April 29 in one year in ten; the first autumn frost comes before November 6 in half of years and before October 20 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- April 81 year in 10 after April 29; 9 in 10 after March 11
- First autumn frost, half of years before
- November 61 year in 10 before October 20; 9 in 10 before November 24
NOAA puts the median frost-free season at 211 days, and the season without a hard freeze (28°F) at 268 days.
A hard freeze (28°F) comes after February 28 in half of springs and before November 22 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Potter Valley in zone 9a in ZIP code 95469, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Potter Valley's NOAA station is in zone 9a: the coldest night of a typical year reaches 21°F (18 complete years).
Frost dates for every NOAA station in California · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00047109; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get in Potter Valley?
In a normal year in Potter Valley, 82 days a year reach 90°F (17 of them 100°F or more), 54 nights fall to 32°F or colder and 96 days bring measurable precipitation.
- Days at 90°F or more
- 82a normal year
- Days at 100°F or more
- 17a normal year
- Nights at 32°F or colder
- 54a normal year
- Days that stay below freezing
- fewer than 1high of 32°F or less
- Days with 0.01 inch of precipitation
- 96a normal year
The highest temperature in this station's record (since 1937) is 116°F, on August 8, 1978; the lowest is 12°F, on December 22, 1990.
The wettest calendar year on that record is 1983, with 84.11 in; the snowiest season is 1964–65, with 10.3 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00047109; records: ACIS (NOAA Regional Climate Centers), station USC00047109. Records use complete months only; a month missing more than three days is left out.
How sunny is Potter Valley?
Over a year 84% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Potter Valley, 4.9 kWh per square metre a day. July is the sunniest month (93%) and December the cloudiest (68%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 71% | 2.2 |
| February | 73% | 3.1 |
| March | 74% | 4.3 |
| April | 79% | 5.8 |
| May | 84% | 7.0 |
| June | 91% | 8.0 |
| July | 93% | 7.9 |
| August | 91% | 6.9 |
| September | 90% | 5.6 |
| October | 85% | 4.0 |
| November | 77% | 2.5 |
| December | 68% | 1.8 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Potter Valley need?
A normal year in Potter Valley brings 3,088 heating degree days, 43% fewer than the median U.S. place (5,373), and 947 cooling degree days, 4% more than the median (908). Five months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 3,836 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 584 | 0 |
| February | 451 | 0 |
| March | 390 | 1 |
| April | 282 | 5 |
| May | 136 | 43 |
| June | 39 | 142 |
| July | 2 | 303 |
| August | 3 | 263 |
| September | 22 | 157 |
| October | 154 | 33 |
| November | 413 | 0 |
| December | 612 | 0 |
| Year (annual) | 3,088 | 947 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00047109. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Has Potter Valley been warmer than normal lately?
2025 averaged 60.7°F, 1.6°F above the 1991-2020 normal of 59.1°F. 4 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 60.9°F | +1.8°F | 37.57 |
| 2022 | 59.6°F | +0.5°F | 26.49 |
| 2023 | 58.8°F | −0.3°F | 43.59 |
| 2024 | 60.5°F | +1.4°F | 61.28 |
| 2025 | 60.7°F | +1.6°F | 43.17 |
Over 44 complete years from 1938 to 2025, the station's annual mean temperature rose at a fitted 1.9°F per century (+0.10°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00047109; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Potter Valley's climate compare?
Potter Valley is warmer than 76 of the other 218 places with their own NOAA record in California, and wetter than 194. Across the 7,247 U.S. stations with normals, its annual mean of 59.1°F is warmer than 72%.
In the Köppen classification computed from these normals, Potter Valley is Csa: temperate, dry-summer, hot summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Potter Valley share this climate record?
Redwood Valley has no NOAA station with 1991-2020 normals of its own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Redwood Valley, CA2,117 people · 8 mi SW
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Potter Valley's climate
What is the coldest month in Potter Valley?
December, with a normal high of 56°F and a normal low of 35°F. The warmest is July (95°F by day, 54°F at night).
Does it snow in Potter Valley?
Rarely: NOAA's normal is no measurable snow a year.
What is the rainiest month in Potter Valley?
December, with 9.77 in of precipitation in a normal year; the driest is July with 0.04 in.
What plant hardiness zone is Potter Valley in?
The USDA's 2023 map puts Potter Valley in zone 9a in ZIP code 95469, the nearest ZIP area. By the same method at Potter Valley's NOAA station, the coldest night of a typical year reaches 21°F (18 years, 1991-2020): zone 9a.
How late can frost come in Potter Valley?
In half of years the last 32°F night comes after April 8; in one year in ten it comes after April 29. Waiting until April 29 leaves about a one-in-ten chance of a later frost.
Nearby and next
- California climateThe statewide normals and every place in the state
- Willits, CA12 miles from this station, 53.1°F a year
- Ukiah, CA17 miles from this station, 59.8°F a year
- Covelo, CA32 miles from this station, 55.8°F a year
- East Park Reservoir, CA33 miles from this station, 59.3°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made