Grass Valley, CA Climate: Temperature & Rain by Month
Pulled from NOAA NCEI 1991–2020 normals →: climate measurements used in PlainClimate's documented score
30-year climate normals (1991-2020) from Grass Valley's primary NOAA station, GRASS VALLEY #2.
The climate verdict for Grass Valley
Water is the standout signal in Grass Valley, California: 53.2 inches of precipitation in a normal year. Against that wet profile, NOAA records an annual average of 56°F. Its climate comfort score of 68/100 (good) lands mid-pack nationally, exceeding 56% of station-mapped location scores.
- 56°F
- average temperature, NOAA 1991-2020 normal
- 68/100
- comfort score, above 56% of station-mapped location scores
- 53.2"
- annual precipitation · 9" snow
- 217 days
- growing season, frost-free days
Grass Valley: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USC00043573 · Grass Valley, CA 56°F mean · 53.2" precip
TEMP-MILD · RANK-UPPER · PHOTO-FINISH · PRCP-WET · SWING-MID · COMF-MID · LOAD-HEAT · STN-1 · BOOK-FULL
- TEMP-MILD 56°F
- RANK-UPPER #4,391
- PHOTO-FINISH ≈ Loraine
- PRCP-WET 53.2"
- SWING-MID 31°F
- COMF-MID 68/100
- LOAD-HEAT 3,963 HDD
- STN-1 USC00043573
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Loraine, CA ( -0.1 °F mean)
Instrument codes from this station's NOAA 1991–2020 normals, mean temperature, corpus warmth rank, photo-finish peer station, precipitation band, seasonal swing, comfort composite, degree-day load, and field book, not a livability rating.
Mean-temperature neighbourhood
Nationwide NOAA normal poles and nearest peers, not a reprint of every CA station list.
- Grass Valley (this station) 56°F
- Cold Covelo, CA 56°F
- Hot N Fork, NC 56°F
- Near Loraine, CA 56°F
- Near Mt Lemmon Willo…, AZ 56°F
Climate Living Index · Grass Valley
Grass Valley: 71/100 · grade B
Grass Valley publishes 5 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 1 missing weight rescale to 100.
PlainClimate-derived for Grass Valley, not an official NOAA rating. Rankings still use Comfort Score 68/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Normal heat + freeze calendar | 0 calendar days | 100/100 · A |
| Frost-free season | 217 days/year | 76/100 · B |
| Snowfall burden | 8.6 inches/year | 65/100 · C |
| Annual temperature balance | 56.1°F · 11.4° from 67.5°F | 63/100 · C |
| Precipitation balance | 53.2 in · 18.2 from 35 in | 35/100 · F |
Grass Valley · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Grass Valley is a temperate Köppen climate: Csa
Coldest-month mean 42.6°F and warmest-month mean 73.1°F place this station in temperate, dry-summer, hot summer climates (Csa). Class Csa is the Peel et al. (2007) label for this station's monthly mean temperature and precipitation normals: temperate, specifically temperate, dry-summer, hot summer.
- Köppen code
- Csa
- Group
- Temperate
- Warmest month
- 73.1°F
- Coldest month
- 42.6°F
Source: official public datasets monthly normals (1991–2020) at the city’s primary station. This is a station classification, not a mapped regional consensus.
National standing · heating-led station
Where Grass Valley sits across the climate record
Three NOAA fields for Grass Valley's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- 64th percentile warmth
- Mid-pack annual mean versus 6,861 station normals.
- Annual precipitation
- Top 13% wettest
- Grass Valley's annual total ranks in the wetter third of 6,352 measured normals.
- Seasonal temperature swing
- Narrower than 90%
- Warmest-to-coldest month gap for Grass Valley is compact versus 6,861 complete station-years.
How Grass Valley compares across U.S. station-mapped locations
Grass Valley's comfort score vs. all station-mapped locations
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
68 Top 44% score exceeds 56% of 6,189 station-mapped location scores
- 0–10: 0 station-mapped locations (0%). Below this entry.
- 10–20: 0 station-mapped locations (0%). Below this entry.
- 20–30: 96 station-mapped locations (2%). Below this entry.
- 30–40: 280 station-mapped locations (5%). Below this entry.
- 40–50: 1,113 station-mapped locations (18%). Below this entry.
- 50–60: 1,329 station-mapped locations (21%). Below this entry.
- 60–70: 1,236 station-mapped locations (20%). This entry sits in this band.
- 70–80: 650 station-mapped locations (11%). Above this entry.
- 80–90: 921 station-mapped locations (15%). Above this entry.
- 90–100: 564 station-mapped locations (9%). Above this entry.
Source NOAA U.S. Climate Normals, PlainClimate comfort index · 1991–2020
Grass Valley's measured station temperature trend
MethodologyAcross 50 complete annual observations from 1967 to 2025, GRASS VALLEY #2 warmed at a fitted rate of 0.24°C per decade. The line shows the fitted change relative to its first year, not raw year-to-year temperatures or a forecast.
- Grass Valley primary station fitted change +0.24 °C/decade
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Snow | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|---|
| January | 54°F (12°C) | 33°F (1°C) | 43°F (6°C) | 9.3" | 0.7" | 15.6 | 0.0 |
| February | 55°F (13°C) | 34°F (1°C) | 45°F (7°C) | 9.0" | 3.0" | 11.0 | 0.0 |
| March | 58°F (14°C) | 37°F (3°C) | 48°F (9°C) | 8.2" | 3.0" | 7.1 | 0.0 |
| April | 63°F (17°C) | 40°F (4°C) | 51°F (11°C) | 4.4" | 0.5" | 3.0 | 0.0 |
| May | 71°F (22°C) | 47°F (8°C) | 59°F (15°C) | 2.5" | 0.0" | 0.1 | 0.5 |
| June | 80°F (27°C) | 53°F (11°C) | 66°F (19°C) | 0.7" | 0.0" | 0.0 | 4.6 |
| July | 88°F (31°C) | 58°F (15°C) | 73°F (23°C) | 0.0" | 0.0" | 0.0 | 13.5 |
| August | 87°F (31°C) | 57°F (14°C) | 72°F (22°C) | 0.1" | 0.0" | 0.0 | 11.8 |
| September | 82°F (28°C) | 52°F (11°C) | 67°F (20°C) | 0.4" | 0.0" | 0.0 | 5.3 |
| October | 72°F (22°C) | 44°F (7°C) | 58°F (15°C) | 2.6" | 0.0" | 0.5 | 0.7 |
| November | 60°F (15°C) | 37°F (3°C) | 48°F (9°C) | 5.5" | 0.2" | 6.9 | 0.0 |
| December | 53°F (11°C) | 33°F (0°C) | 43°F (6°C) | 10.5" | 1.2" | 17.2 | 0.0 |
The year, day by day
The calendar barely moves in Grass Valley: no date carries a normal high of 90°F or a normal low at freezing. The year runs between 32°F near December 20 and 89°F near July 22.
No freezing date
Not one calendar date in the 1991–2020 record carries a normal low at or below 32°F. The coldest normal low of the year is 32°F around December 20.
Where the wet dates fall
The likeliest wet date is February 18, when 42% of years recorded at least a hundredth of an inch. The driest is July 18 at 1%. Summed across the calendar, that is about 82 wet dates a year.
The widest day
August 24 carries the biggest normal gap between afternoon and dawn, 31°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for Grass Valley.
Where Grass Valley Stands Nationally
The normal water year runs well above the national norm at roughly 53 inches.
Grass Valley earns one nationally notable standing (outer quintile) against 6,860 NOAA 1991–2020 normals stations, middle-of-the-pack metrics stay silent here.
Monthly Precipitation
Average monthly rainfall and snowfall
Snow: 0.7"
12.8 days with precipitation
Snow: 3.0"
11.7 days with precipitation
Snow: 3.0"
12.2 days with precipitation
Snow: 0.5"
8.5 days with precipitation
5.9 days with precipitation
2.7 days with precipitation
0.2 days with precipitation
0.8 days with precipitation
1.6 days with precipitation
4.4 days with precipitation
Snow: 0.2"
8.4 days with precipitation
Snow: 1.2"
12.3 days with precipitation
Grass Valley's wet season runs through the cold months
December, January and February carry 54% of the year's precipitation here, while June through August contribute 2%. That is the cool-season-dominant pattern of the West Coast and the higher inland West, where storm tracks swing south in winter and summer turns dry; the thermometer meanwhile shows a 30.5°F seasonal spread.
- Wettest month
- December, 10.5"
- Driest month
- July, 0.0"
- Wettest three months
- December, January, February (54% of the year)
Shares are computed from this station's own 1991-2020 monthly precipitation normals. A cool-season label means the December-February share reaches 35%. Where snow falls, the monthly figures above report liquid-equivalent precipitation, so a wet winter month is not necessarily a rainy one.
When it rains in Grass Valley, it arrives in quantity
53.2" of precipitation falls across only about 82 wet days here, averaging 0.65 inches each. Fewer days carry more water: the year's total is delivered in comparatively heavy events rather than persistent damp.
- Days with measurable precipitation
- about 82 a year, 22% of all days
- Average depth per wet day
- 0.65 inches
- Most wet days
- January, about 13
- Fewest wet days
- July, about 0
A wet day is one recording at least 0.01 inches. These are 1991-2020 normals: they describe an average year, and a per-day average is not a forecast of any individual storm.
Snow reaches Grass Valley, but rarely amounts to much
The normals record 8.6 inches of snow a year here, most likely in February. That is a real but marginal amount: enough that snow is part of the local record, not enough to define the winter.
A figure in this range usually reflects a handful of events that melt quickly rather than a season of accumulation; about 3 days a year record any measurable snow at all.
NOAA 1991-2020 normals. An average across thirty years can smooth away a single heavy winter, so a small annual figure does not mean a significant snowfall is impossible.
Frost Dates & Growing Season
First Fall Freeze
November 13
50% probability date
Last Spring Freeze
April 10
50% probability date
Growing Season
217 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
3,963
Higher = more heating needed
Cooling Degree Days
749
Higher = more cooling needed
Warmest Month
July
Coldest Month
December
Nationwide similar cities
Other rankable U.S. places outside CA closest to Grass Valley on two NOAA annual-normal axes (mean temperature and annual precipitation). Chip rows use distinct link sets.
Closest by average temperature
Nearest out-of-state peers by annual mean temperature (56°F here).
- Bushland, TX 56°F · 0.0°F off
- Colorado City, AZ 56°F · 0.0°F off
- Cullowhee, NC 56°F · 0.0°F off
- Eldon, MO 56°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (53.2" here), excluding temperature-peer places.
- Williamston, NC 53.2" · 0.0" off
- Glen St Mary, FL 53.2" · 0.0" off
- Stanton, KY 53.2" · 0.0" off
- Waldron, AR 53.2" · 0.0" off
Data-derived climate profile
How Grass Valley's climate pattern fits together
heating led · wet · mid swing
Grass Valley's energy balance leans toward cold weather: 3,963 annual heating degree days against 749 for cooling. Its 30.5°F seasonal range still makes the monthly rows more useful than the annual average alone.
Grass Valley's frost-free season lasts about 217 days, a middle-length window whose endpoints matter more than the annual average. It describes freeze probability, not year-specific planting conditions.
July and December mark the typical warm and cold ends of the calendar in Grass Valley's middle-range seasonal profile. The measured spread is 30.5°F. The annual average is 56°F. Neither the annual mean nor one extreme month represents the full calendar on its own.
Alongside its heating load, Grass Valley carries 53.2 inches of precipitation in a normal year, inside PlainClimate's wet range. Annual snowfall totals 8.6 inches. That distinction matters because a wet annual total can arrive as rain, snow, or a mixture at different times.
These labels group NOAA 1991-2020 normals from Grass Valley's primary station, so the winter figures are a thirty-year average and not a floor: a single hard season can run well below them. Treat each band as a descriptive range for Grass Valley, not an official NOAA class or a year-ahead forecast.
Questions about Grass Valley's climate
How much rain does Grass Valley get? ▼
How many days above 90°F does Grass Valley get? ▼
How much energy does heating and cooling require in Grass Valley? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Grass Valley's primary station: GRASS VALLEY #2 (USC00043573). For informational purposes only.
Place identity: U.S. Census Bureau 2024 Gazetteer places. The 2024 Census Gazetteer identifies the exact name-and-state match as an incorporated place (GEOID 0630798). Match rule for Grass Valley: exact normalized name + state only, no fuzzy expansion, so nearby differently spelled facilities stay unmatched.
On this page every temperature, precipitation, and derived score for Grass Valley comes from its primary NOAA station record. No figure on this page is typed in by an editor - each value is rendered from NOAA 1991-2020 U.S. Climate Normals. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 1991–2020 normals.