New Melones Dam Headquarters, California climate: Climate normals at a NOAA weather station
New Melones Dam Headquarters's normal year runs from 38°F December nights to 97°F July afternoons, with 29.8 inches of precipitation and less than an inch of snow (0.2 in) a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 17.2°C, December lows of 3°C, July highs of 36°C, 756 mm of precipitation a year.
- NOAA stationNew Melones Dam Headquarters
- Station IDUSC00046174
- Location38.00°N 120.49°W
- Elevation960 ft (293 m)
On October 22, the normal high in New Melones Dam Headquarters is 77°F and the normal low 51°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 New Melones Dam Headquarters.
- Jan 57° 38°
- Feb 61° 40°
- Mar 65° 44°
- Apr 70° 46°
- May 79° 52°
- Jun 89° 59°
- Jul 97° 65°
- Aug 96° 65°
- Sep 91° 60°
- Oct 80° 52°
- Nov 66° 44°
- Dec 57° 38°
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 New Melones Dam Headquarters each month?
July is the warmest month, with normal highs of 97°F; December the coldest, with normal lows of 38°F. The most precipitation falls in January (5.85 in), the least in July (0.03 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 57°F | 38°F | 47.8°F | 5.85 | 13 | <1 | 4 | 9 h 50 min |
| February | 61°F | 40°F | 50.1°F | 4.85 | 11 | <1 | 2 | 10 h 50 min |
| March | 65°F | 44°F | 54.2°F | 4.77 | 11 | <1 | 1 | 11 h 50 min |
| April | 70°F | 46°F | 57.9°F | 2.58 | 7 | <1 | <1 | 13 h 10 min |
| May | 79°F | 52°F | 65.9°F | 1.48 | 5 | 5 | <1 | 14 h 10 min |
| June | 89°F | 59°F | 74.2°F | 0.36 | 2 | 16 | <1 | 14 h 50 min |
| July | 97°F | 65°F | 81.3°F | 0.03 | <1 | 28 | <1 | 14 h 30 min |
| August | 96°F | 65°F | 80.3°F | 0.04 | <1 | 27 | <1 | 13 h 40 min |
| September | 91°F | 60°F | 75.5°F | 0.21 | 1 | 18 | <1 | 12 h 30 min |
| October | 80°F | 52°F | 66.0°F | 1.51 | 4 | 4 | <1 | 11 h 20 min |
| November | 66°F | 44°F | 55.0°F | 2.91 | 8 | <1 | 1 | 10 h 10 min |
| December | 57°F | 38°F | 47.6°F | 5.16 | 12 | <1 | 5 | 9 h 30 min |
| Year (annual) | 76°F | 50°F | 63.0°F | 29.75 | 75 | 98 | 13 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 14°C | 3°C | 8.8°C | 149 mm |
| February | 16°C | 4°C | 10.1°C | 123 mm |
| March | 18°C | 6°C | 12.3°C | 121 mm |
| April | 21°C | 8°C | 14.4°C | 66 mm |
| May | 26°C | 11°C | 18.8°C | 38 mm |
| June | 32°C | 15°C | 23.4°C | 9 mm |
| July | 36°C | 19°C | 27.4°C | 1 mm |
| August | 36°C | 18°C | 26.8°C | 1 mm |
| September | 33°C | 16°C | 24.2°C | 5 mm |
| October | 27°C | 11°C | 18.9°C | 38 mm |
| November | 19°C | 7°C | 12.8°C | 74 mm |
| December | 14°C | 3°C | 8.7°C | 131 mm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00046174; 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 New Melones Dam Headquarters?
Normal highs sit between 65°F and 85°F in April, May, October and November. 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 USC00046174.
When is the last frost at New Melones Dam Headquarters?
In New Melones Dam Headquarters, the last spring frost (32°F) comes after February 20 in half of years and after April 7 in one year in ten; the first autumn frost comes before December 11 in half of years and before November 24 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
- February 201 year in 10 after April 7; 9 in 10 after January 10
- First autumn frost, half of years before
- December 111 year in 10 before November 24; 9 in 10 before January 8
NOAA puts the median frost-free season at 290 days, and the season without a hard freeze (28°F) at 358 days.
A hard freeze (28°F) comes after January 6 in half of springs and before December 24 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts New Melones Dam Headquarters in zone 9a in ZIP code 95251, 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 9b: the coldest night of a typical year reaches 27°F (24 complete years); the map interpolates between stations and terrain, so the station and the ZIP area can differ by half a zone.
Frost dates for every NOAA station in California · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00046174; 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 New Melones Dam Headquarters?
In a normal year in New Melones Dam Headquarters, 98 days a year reach 90°F (28 of them 100°F or more), 13 nights fall to 32°F or colder and 75 days bring measurable precipitation.
- Days at 90°F or more
- 98a normal year
- Days at 100°F or more
- 28a normal year
- Nights at 32°F or colder
- 13a normal year
- Days that stay below freezing
- fewer than 1high of 32°F or less
- Days with 0.01 inch of precipitation
- 75a normal year
The highest temperature in this station's record (since 1992) is 114°F, on July 24, 2006; the lowest is 19°F, on December 16, 2008.
The wettest calendar year on that record is 1998, with 50.29 in.
Source: NOAA NCEI 1991-2020 annual normals, station USC00046174; records: ACIS (NOAA Regional Climate Centers), station USC00046174. Records use complete months only; a month missing more than three days is left out.
How sunny is it at New Melones Dam Headquarters?
Over a year 86% of the sunlight that would reach the ground under clear skies gets through the clouds at New Melones Dam Headquarters, 5.2 kWh per square metre a day. August is the sunniest month (97%) and December the cloudiest (70%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 72% | 2.4 |
| February | 72% | 3.2 |
| March | 74% | 4.5 |
| April | 78% | 5.9 |
| May | 86% | 7.3 |
| June | 94% | 8.4 |
| July | 97% | 8.3 |
| August | 97% | 7.5 |
| September | 94% | 6.0 |
| October | 89% | 4.4 |
| November | 80% | 2.8 |
| December | 70% | 2.1 |
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 New Melones Dam Headquarters record?
A normal year at New Melones Dam Headquarters brings 2,547 heating degree days, 53% fewer than the median U.S. place (5,373), and 1,842 cooling degree days, 2.0 times 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 5,108 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 535 | 0 |
| February | 416 | 0 |
| March | 338 | 2 |
| April | 231 | 19 |
| May | 87 | 115 |
| June | 15 | 292 |
| July | 0 | 504 |
| August | 0 | 476 |
| September | 8 | 321 |
| October | 74 | 107 |
| November | 305 | 6 |
| December | 539 | 0 |
| Year (annual) | 2,547 | 1,842 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00046174. 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 New Melones Dam Headquarters been warmer than normal?
2025 averaged 63.5°F, 0.5°F above the 1991-2020 normal of 63.0°F. 4 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 64.1°F | +1.1°F | 24.12 |
| 2022 | 63.9°F | +0.9°F | 20.77 |
| 2023 | 62.3°F | −0.7°F | 36.63 |
| 2024 | 65.0°F | +2.0°F | 31.16 |
| 2025 | 63.5°F | +0.5°F | 26.09 |
Source: observed years: ACIS, station USC00046174. A year counts only with all twelve months complete.
How does New Melones Dam Headquarters's climate compare?
New Melones Dam Headquarters is warmer than 148 of the 219 places with their own NOAA record in California, and wetter than 167. Across the 7,247 U.S. stations with normals, its annual mean of 63.0°F is warmer than 83%.
In the Köppen classification computed from these normals, New Melones Dam Headquarters 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 New Melones Dam Headquarters share this climate record?
9 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.
- Copperopolis, CA4,644 people · 9 mi SW
- Angels, CA3,728 people · 6 mi NW
- Columbia, CA2,645 people · 4 mi NE
- Murphys, CA1,821 people · 9 mi N
- Orange Blossom, CA1,210 people · 17 mi SW
- Tuttletown, CA835 people · 2 mi E
- Vallecito, CA535 people · 6 mi N
- Douglas Flat, CA187 people · 8 mi N
- Knights Ferry, CA81 people · 16 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 New Melones Dam Headquarters's climate
What is the coldest month at New Melones Dam Headquarters?
December, with a normal high of 57°F and a normal low of 38°F. The warmest is July (97°F by day, 65°F at night).
Does it snow at New Melones Dam Headquarters?
Rarely: NOAA's normal is 0.2 inch a year.
What is the rainiest month at New Melones Dam Headquarters?
January, with 5.85 in of precipitation in a normal year; the driest is July with 0.03 in.
What plant hardiness zone is New Melones Dam Headquarters in?
The USDA's 2023 map puts New Melones Dam Headquarters in zone 9a in ZIP code 95251, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches 27°F (24 years, 1991-2020): zone 9b.
How late can frost come at New Melones Dam Headquarters?
In half of years the last 32°F night comes after February 20; in one year in ten it comes after April 7. Waiting until April 7 leaves about a one-in-ten chance of a later frost.
Nearby and next
- California climateThe statewide normals and every place in the state
- Sonora, CA6 miles from this station, 57.7°F a year
- Groveland, CA18 miles from this station, 55.9°F a year
- Calaveras Big Trees, CA21 miles from this station, 50.3°F a year
- Camp Pardee, CA25 miles from this station, 62.5°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made