Stony Gorge Reservoir, California climate: Climate normals at a NOAA weather station
Stony Gorge Reservoir's normal year runs from 33°F December nights to 96°F July afternoons, with 21.4 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 15.5°C, December lows of 1°C, July highs of 36°C, 543 mm of precipitation a year.
- NOAA stationStony Gorge Reservoir
- Station IDUSC00048587
- Location39.59°N 122.53°W
- Elevation800 ft (244 m)
On October 23, the normal high in Stony Gorge Reservoir is 75°F and the normal low 43°F, and the chance of measurable rain or snow is 14%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Stony Gorge Reservoir.
- Jan 56° 34°
- Feb 60° 36°
- Mar 64° 38°
- Apr 70° 41°
- May 80° 48°
- Jun 89° 55°
- Jul 96° 61°
- Aug 95° 59°
- Sep 90° 54°
- Oct 79° 46°
- Nov 64° 37°
- Dec 56° 33°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like at Stony Gorge Reservoir each month?
July is the warmest month, with normal highs of 96°F; December the coldest, with normal lows of 33°F. The most precipitation falls in January (4.50 in), the least in July (0.05 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 56°F | 34°F | 44.9°F | 4.50 | 12 | <1 | 14 | 9 h 40 min |
| February | 60°F | 36°F | 47.5°F | 4.02 | 10 | <1 | 9 | 10 h 40 min |
| March | 64°F | 38°F | 51.1°F | 2.75 | 9 | <1 | 6 | 11 h 50 min |
| April | 70°F | 41°F | 55.7°F | 1.35 | 6 | <1 | 3 | 13 h 10 min |
| May | 80°F | 48°F | 63.7°F | 1.07 | 5 | 6 | <1 | 14 h 20 min |
| June | 89°F | 55°F | 72.1°F | 0.54 | 2 | 16 | <1 | 15 h |
| July | 96°F | 61°F | 78.4°F | 0.05 | <1 | 27 | <1 | 14 h 40 min |
| August | 95°F | 59°F | 76.7°F | 0.05 | <1 | 25 | <1 | 13 h 50 min |
| September | 90°F | 54°F | 71.9°F | 0.12 | 1 | 18 | <1 | 12 h 30 min |
| October | 79°F | 46°F | 62.1°F | 0.93 | 4 | 4 | <1 | 11 h 10 min |
| November | 64°F | 37°F | 50.8°F | 2.00 | 7 | <1 | 8 | 10 h |
| December | 56°F | 33°F | 44.3°F | 3.98 | 12 | <1 | 17 | 9 h 20 min |
| Year (annual) | 75°F | 45°F | 59.9°F | 21.36 | 68 | 97 | 57 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 13°C | 1°C | 7.2°C | 114 mm |
| February | 15°C | 2°C | 8.6°C | 102 mm |
| March | 18°C | 3°C | 10.6°C | 70 mm |
| April | 21°C | 5°C | 13.2°C | 34 mm |
| May | 26°C | 9°C | 17.6°C | 27 mm |
| June | 32°C | 13°C | 22.3°C | 14 mm |
| July | 36°C | 16°C | 25.8°C | 1 mm |
| August | 35°C | 15°C | 24.8°C | 1 mm |
| September | 32°C | 12°C | 22.2°C | 3 mm |
| October | 26°C | 8°C | 16.7°C | 24 mm |
| November | 18°C | 3°C | 10.4°C | 51 mm |
| December | 13°C | 1°C | 6.8°C | 101 mm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00048587; 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.
Which months are mildest at Stony Gorge Reservoir?
Normal highs sit between 65°F and 85°F in April, May and October. Of those, October has the fewest days with rain (4).
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 USC00048587.
When is the last frost at Stony Gorge Reservoir?
In Stony Gorge Reservoir, the last spring frost (32°F) comes after April 5 in half of years and after April 24 in one year in ten; the first autumn frost comes before November 13 in half of years and before October 29 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 51 year in 10 after April 24; 9 in 10 after March 8
- First autumn frost, half of years before
- November 131 year in 10 before October 29; 9 in 10 before November 29
NOAA puts the median frost-free season at 220 days, and the season without a hard freeze (28°F) at 271 days.
A hard freeze (28°F) comes after March 1 in half of springs and before November 29 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Stony Gorge Reservoir in zone 9a in ZIP code 95939, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, the station is in zone 9a: the coldest night of a typical year reaches 21°F (29 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 USC00048587; 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 at Stony Gorge Reservoir?
In a normal year in Stony Gorge Reservoir, 97 days a year reach 90°F (26 of them 100°F or more), 57 nights fall to 32°F or colder and 68 days bring measurable precipitation.
- Days at 90°F or more
- 97a normal year
- Days at 100°F or more
- 26a normal year
- Nights at 32°F or colder
- 57a normal year
- Days that stay below freezing
- fewer than 1high of 32°F or less
- Days with 0.01 inch of precipitation
- 68a normal year
The highest temperature in this station's record (since 1926) is 116°F, on July 16, 1972; the lowest is 5°F, on December 11, 1932.
The wettest calendar year on that record is 1998, with 41.80 in; the snowiest season is 1951–52, with 17.8 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00048587; records: ACIS (NOAA Regional Climate Centers), station USC00048587. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Stony Gorge Reservoir?
Over a year 88% of the sunlight that would reach the ground under clear skies gets through the clouds at Stony Gorge Reservoir, 5.2 kWh per square metre a day. July is the sunniest month (98%) and December the cloudiest (70%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 72% | 2.2 |
| February | 76% | 3.2 |
| March | 78% | 4.5 |
| April | 83% | 6.0 |
| May | 88% | 7.3 |
| June | 94% | 8.2 |
| July | 98% | 8.3 |
| August | 97% | 7.3 |
| September | 95% | 5.9 |
| October | 89% | 4.2 |
| November | 80% | 2.6 |
| December | 70% | 1.9 |
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 many heating and cooling degree days does Stony Gorge Reservoir record?
A normal year at Stony Gorge Reservoir brings 3,190 heating degree days, 41% fewer than the median U.S. place (5,373), and 1,364 cooling degree days, 50% 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 4,253 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 622 | 0 |
| February | 489 | 0 |
| March | 431 | 0 |
| April | 286 | 5 |
| May | 116 | 75 |
| June | 22 | 233 |
| July | 1 | 416 |
| August | 1 | 363 |
| September | 16 | 221 |
| October | 140 | 50 |
| November | 426 | 0 |
| December | 642 | 0 |
| Year (annual) | 3,190 | 1,364 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00048587. 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.
Have recent years at Stony Gorge Reservoir been warmer than normal?
2025 averaged 61.2°F, 1.3°F above the 1991-2020 normal of 59.9°F. 5 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 61.7°F | +1.8°F | 14.60 |
| 2022 | 61.4°F | +1.5°F | 10.24 |
| 2023 | 60.2°F | +0.3°F | 30.26 |
| 2024 | 61.2°F | +1.3°F | 30.30 |
| 2025 | 61.2°F | +1.3°F | – |
Over 85 complete years from 1928 to 2025, the station's annual mean temperature rose at a fitted 1.0°F per century (+0.06°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00048587; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Stony Gorge Reservoir's climate compare?
Stony Gorge Reservoir is warmer than 93 of the 219 places with their own NOAA record in California, and wetter than 142. Across the 7,247 U.S. stations with normals, its annual mean of 59.9°F is warmer than 75%.
In the Köppen classification computed from these normals, Stony Gorge Reservoir 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 Stony Gorge Reservoir share this climate record?
2 places have no NOAA station with 1991-2020 normals of their 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.
- Paskenta, CA61 people · 21 mi N
- Elk Creek, CA52 people · 1 mi N
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 Stony Gorge Reservoir's climate
What is the coldest month at Stony Gorge Reservoir?
December, with a normal high of 56°F and a normal low of 33°F. The warmest is July (96°F by day, 61°F at night).
Does it snow at Stony Gorge Reservoir?
Rarely: NOAA's normal is no measurable snow a year.
What is the rainiest month at Stony Gorge Reservoir?
January, with 4.50 in of precipitation in a normal year; the driest is July with 0.05 in.
What plant hardiness zone is Stony Gorge Reservoir in?
The USDA's 2023 map puts Stony Gorge Reservoir in zone 9a in ZIP code 95939, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches 21°F (29 years, 1991-2020): zone 9a.
How late can frost come at Stony Gorge Reservoir?
In half of years the last 32°F night comes after April 5; in one year in ten it comes after April 24. Waiting until April 24 leaves about a one-in-ten chance of a later frost.
Nearby and next
- California climateThe statewide normals and every place in the state
- Willows, CA13 miles from this station, 63.7°F a year
- East Park Reservoir, CA16 miles from this station, 59.3°F a year
- Orland, CA21 miles from this station, 62.5°F a year
- Potter Valley, CA35 miles from this station, 59.1°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made