Graton, California climate: Normal weather by month, frost dates and records
Graton's normal year runs from 37°F December nights to 84°F August afternoons, with 39.9 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 14.3°C, December lows of 3°C, August highs of 29°C, 1,014 mm of precipitation a year.
- NOAA stationGraton
- Station IDUSC00043578
- Location38.43°N 122.86°W
- Elevation200 ft (61 m)
- From the centerunder 1 mile
- Population (census place)1,819
On October 23, the normal high in Graton is 77°F and the normal low 43°F, and the chance of measurable rain or snow is 17%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Graton.
- Jan 58° 37°
- Feb 62° 39°
- Mar 66° 41°
- Apr 70° 42°
- May 75° 46°
- Jun 81° 48°
- Jul 83° 51°
- Aug 84° 50°
- Sep 84° 48°
- Oct 78° 44°
- Nov 67° 40°
- Dec 58° 37°
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 Graton each month?
August is the warmest month, with normal highs of 84°F; December the coldest, with normal lows of 37°F. The most precipitation falls in December (8.34 in), the least in July (0.01 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 58°F | 37°F | 47.7°F | 7.88 | 13 | <1 | 11 | 9 h 50 min |
| February | 62°F | 39°F | 50.7°F | 7.48 | 12 | <1 | 7 | 10 h 40 min |
| March | 66°F | 41°F | 53.3°F | 5.18 | 11 | <1 | 4 | 11 h 50 min |
| April | 70°F | 42°F | 56.2°F | 2.58 | 7 | 1 | 2 | 13 h 10 min |
| May | 75°F | 46°F | 60.4°F | 1.41 | 4 | 2 | <1 | 14 h 10 min |
| June | 81°F | 48°F | 64.8°F | 0.41 | 2 | 6 | <1 | 14 h 50 min |
| July | 83°F | 51°F | 66.5°F | 0.01 | <1 | 6 | <1 | 14 h 40 min |
| August | 84°F | 50°F | 67.1°F | 0.06 | 1 | 8 | <1 | 13 h 40 min |
| September | 84°F | 48°F | 65.9°F | 0.18 | 2 | 8 | <1 | 12 h 30 min |
| October | 78°F | 44°F | 61.2°F | 1.98 | 4 | 4 | 1 | 11 h 20 min |
| November | 67°F | 40°F | 53.3°F | 4.43 | 9 | <1 | 6 | 10 h 10 min |
| December | 58°F | 37°F | 47.2°F | 8.34 | 13 | <1 | 13 | 9 h 30 min |
| Year (annual) | 72°F | 44°F | 57.8°F | 39.94 | 78 | 34 | 43 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 14°C | 3°C | 8.7°C | 200 mm |
| February | 17°C | 4°C | 10.4°C | 190 mm |
| March | 19°C | 5°C | 11.8°C | 132 mm |
| April | 21°C | 6°C | 13.4°C | 66 mm |
| May | 24°C | 8°C | 15.8°C | 36 mm |
| June | 27°C | 9°C | 18.2°C | 10 mm |
| July | 28°C | 10°C | 19.2°C | 0 mm |
| August | 29°C | 10°C | 19.5°C | 2 mm |
| September | 29°C | 9°C | 18.8°C | 5 mm |
| October | 26°C | 7°C | 16.2°C | 50 mm |
| November | 19°C | 4°C | 11.8°C | 113 mm |
| December | 14°C | 3°C | 8.4°C | 212 mm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00043578; 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 Graton?
Normal highs sit between 65°F and 85°F in March, April, May, June, July, August, September, October and November. Of those, July has the fewest days with rain (0).
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 USC00043578.
When is the last frost in Graton?
In Graton, the last spring frost (32°F) comes after March 20 in half of years and after April 19 in one year in ten; the first autumn frost comes before November 13 in half of years and before October 26 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
- March 201 year in 10 after April 19; 9 in 10 after February 12
- First autumn frost, half of years before
- November 131 year in 10 before October 26; 9 in 10 before December 6
NOAA puts the median frost-free season at 240 days, and the season without a hard freeze (28°F) at 307 days.
A hard freeze (28°F) comes after February 1 in half of springs and before December 3 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Graton in zone 9a in ZIP code 95444. By the map's own method, the average of each year's coldest night over 1991-2020, Graton's NOAA station is in zone 9a: the coldest night of a typical year reaches 23°F (30 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 USC00043578; 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 Graton?
In a normal year in Graton, 34 days a year reach 90°F (5 of them 100°F or more), 43 nights fall to 32°F or colder and 78 days bring measurable precipitation.
- Days at 90°F or more
- 34a normal year
- Days at 100°F or more
- 5a normal year
- Nights at 32°F or colder
- 43a normal year
- Days that stay below freezing
- fewer than 1high of 32°F or less
- Days with 0.01 inch of precipitation
- 78a normal year
The highest temperature in this station's record (since 1926) is 115°F, on September 6, 2022; the lowest is 14°F, on December 23, 1990.
The wettest calendar year on that record is 1983, with 84.65 in.
Source: NOAA NCEI 1991-2020 annual normals, station USC00043578; records: ACIS (NOAA Regional Climate Centers), station USC00043578. Records use complete months only; a month missing more than three days is left out.
How sunny is Graton?
Over a year 87% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Graton, 5.1 kWh per square metre a day. July is the sunniest month (95%) and December the cloudiest (72%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 74% | 2.3 |
| February | 77% | 3.3 |
| March | 78% | 4.6 |
| April | 84% | 6.1 |
| May | 88% | 7.3 |
| June | 93% | 8.1 |
| July | 95% | 8.0 |
| August | 94% | 7.1 |
| September | 93% | 5.8 |
| October | 88% | 4.2 |
| November | 81% | 2.8 |
| December | 72% | 2.0 |
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 Graton need?
A normal year in Graton brings 2,927 heating degree days, 46% fewer than the median U.S. place (5,373), and 327 cooling degree days, 64% fewer 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 3,190 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 538 | 0 |
| February | 402 | 0 |
| March | 363 | 0 |
| April | 267 | 3 |
| May | 160 | 16 |
| June | 60 | 54 |
| July | 26 | 74 |
| August | 22 | 85 |
| September | 43 | 69 |
| October | 143 | 25 |
| November | 353 | 1 |
| December | 550 | 0 |
| Year (annual) | 2,927 | 327 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00043578. 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 Graton been warmer than normal lately?
2025 averaged 58.1°F, 0.3°F above the 1991-2020 normal of 57.8°F. 3 of the 3 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 58.4°F | +0.6°F | 51.30 |
| 2022 | 59.2°F | +1.4°F | 23.13 |
| 2025 | 58.1°F | +0.3°F | 29.09 |
Over 87 complete years from 1926 to 2025, the station's annual mean temperature rose at a fitted 2.8°F per century (+0.15°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00043578; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Graton's climate compare?
Graton is warmer than 59 of the other 218 places with their own NOAA record in California, and wetter than 186. Across the 7,247 U.S. stations with normals, its annual mean of 57.8°F is warmer than 69%.
In the Köppen classification computed from these normals, Graton is Csb: temperate, dry-summer, warm 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 Graton share this climate record?
4 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.
- Sebastopol, CA7,388 people · 3 mi SE
- Guerneville, CA4,522 people · 9 mi NW
- Forestville, CA3,862 people · 4 mi N
- Bloomfield, CA294 people · 8 mi S
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 Graton's climate
What is the coldest month in Graton?
December, with a normal high of 58°F and a normal low of 37°F. The warmest is August (84°F by day, 50°F at night).
Does it snow in Graton?
Rarely: NOAA's normal is no measurable snow a year.
What is the rainiest month in Graton?
December, with 8.34 in of precipitation in a normal year; the driest is July with 0.01 in.
What plant hardiness zone is Graton in?
The USDA's 2023 map puts Graton in zone 9a in ZIP code 95444. By the same method at Graton's NOAA station, the coldest night of a typical year reaches 23°F (30 years, 1991-2020): zone 9a.
How late can frost come in Graton?
In half of years the last 32°F night comes after March 20; in one year in ten it comes after April 19. Waiting until April 19 leaves about a one-in-ten chance of a later frost.
Nearby and next
- California climateThe statewide normals and every place in the state
- Santa Rosa, CA6 miles from this station, 58.1°F a year
- Occidental, CA6 miles from this station, 57.6°F a year
- Bodega, CA14 miles from this station, 53.5°F a year
- Healdsburg, CA14 miles from this station, 60.2°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made