Ben Lomond, California climate: Normal weather by month, frost dates and records
Ben Lomond's normal year runs from 37°F December nights to 90°F August afternoons, with 49.6 inches of precipitation and less than an inch of snow (0.1 in) a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 15.8°C, December lows of 3°C, August highs of 32°C, 1,261 mm of precipitation a year.
- NOAA stationBen Lomond #4
- Station IDUSC00040673
- Location37.09°N 122.08°W
- Elevation420 ft (128 m)
- From the centerunder 1 mile
- Population (census place)6,849
On October 23, the normal high in Ben Lomond is 81°F and the normal low 43°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 Ben Lomond.
- Jan 65° 37°
- Feb 67° 39°
- Mar 71° 41°
- Apr 75° 42°
- May 80° 46°
- Jun 86° 49°
- Jul 88° 51°
- Aug 90° 51°
- Sep 89° 49°
- Oct 83° 44°
- Nov 71° 40°
- Dec 64° 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 Ben Lomond each month?
August is the warmest month, with normal highs of 90°F; December the coldest, with normal lows of 37°F. The most precipitation falls in December (10.43 in), the least in July (0.01 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 65°F | 37°F | 51.0°F | 10.42 | 12 | <1 | 9 | 9 h 50 min |
| February | 67°F | 39°F | 52.9°F | 9.68 | 12 | <1 | 6 | 10 h 50 min |
| March | 71°F | 41°F | 55.6°F | 7.00 | 10 | 1 | 4 | 11 h 50 min |
| April | 75°F | 42°F | 58.5°F | 3.28 | 7 | 2 | 1 | 13 h 10 min |
| May | 80°F | 46°F | 62.6°F | 1.24 | 4 | 4 | <1 | 14 h 10 min |
| June | 86°F | 49°F | 67.1°F | 0.24 | 2 | 8 | <1 | 14 h 40 min |
| July | 88°F | 51°F | 69.6°F | 0.01 | <1 | 10 | <1 | 14 h 30 min |
| August | 90°F | 51°F | 70.2°F | 0.04 | 1 | 12 | <1 | 13 h 40 min |
| September | 89°F | 49°F | 68.7°F | 0.12 | 1 | 11 | <1 | 12 h 30 min |
| October | 83°F | 44°F | 63.6°F | 2.17 | 4 | 7 | 1 | 11 h 20 min |
| November | 71°F | 40°F | 55.4°F | 5.00 | 8 | 1 | 5 | 10 h 10 min |
| December | 64°F | 37°F | 50.2°F | 10.43 | 12 | <1 | 11 | 9 h 40 min |
| Year (annual) | 77°F | 44°F | 60.4°F | 49.63 | 72 | 54 | 37 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 18°C | 3°C | 10.6°C | 265 mm |
| February | 19°C | 4°C | 11.6°C | 246 mm |
| March | 21°C | 5°C | 13.1°C | 178 mm |
| April | 24°C | 5°C | 14.7°C | 83 mm |
| May | 26°C | 8°C | 17.0°C | 31 mm |
| June | 30°C | 9°C | 19.5°C | 6 mm |
| July | 31°C | 11°C | 20.9°C | 0 mm |
| August | 32°C | 11°C | 21.2°C | 1 mm |
| September | 31°C | 9°C | 20.4°C | 3 mm |
| October | 28°C | 7°C | 17.6°C | 55 mm |
| November | 22°C | 4°C | 13.0°C | 127 mm |
| December | 18°C | 3°C | 10.1°C | 265 mm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00040673; 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 Ben Lomond?
Normal highs sit between 65°F and 85°F in February, March, 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 USC00040673.
When is the last frost in Ben Lomond?
In Ben Lomond, the last spring frost (32°F) comes after March 25 in half of years and after April 21 in one year in ten; the first autumn frost comes before November 11 in half of years and before October 18 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 251 year in 10 after April 21; 9 in 10 after February 17
- First autumn frost, half of years before
- November 111 year in 10 before October 18; 9 in 10 before December 4
NOAA puts the median frost-free season at 231 days, and the season without a hard freeze (28°F) at 302 days.
A hard freeze (28°F) comes after February 6 in half of springs and before December 4 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Ben Lomond in zones 9a to 9b across its 2 ZIP code areas (9a in 95005, the largest). By the map's own method, the average of each year's coldest night over 1991-2020, Ben Lomond's NOAA station is in zone 9a: the coldest night of a typical year reaches 24°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 USC00040673; 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.
What hardiness zone is each Ben Lomond ZIP code in?
The USDA's 2023 map gives each ZIP code area one zone. Ben Lomond's 2 ZIP code areas run from zone 9a to 9b: 1 in 9a and 1 in 9b. Each ZIP's frost dates are in the frost tool.
Source: USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; ZIP areas in the place: Census Bureau 2020 ZCTA-to-place relationship file. A ZIP area counts when at least a tenth of its land (and 0.5 km²) lies in the place.
How hot and how cold does it get in Ben Lomond?
In a normal year in Ben Lomond, 54 days a year reach 90°F (11 of them 100°F or more), 37 nights fall to 32°F or colder and 72 days bring measurable precipitation.
- Days at 90°F or more
- 54a normal year
- Days at 100°F or more
- 11a normal year
- Nights at 32°F or colder
- 37a normal year
- Days that stay below freezing
- fewer than 1high of 32°F or less
- Days with 0.01 inch of precipitation
- 72a normal year
The highest temperature in this station's record (since 1937) is 121°F, on September 6, 2020; the lowest is 15°F, on December 23, 1990.
The wettest calendar year on that record is 1983, with 100.37 in; the snowiest season is 1975–76, with 2.5 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00040673; records: ACIS (NOAA Regional Climate Centers), station USC00040673. Records use complete months only; a month missing more than three days is left out.
How sunny is Ben Lomond?
Over a year 80% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Ben Lomond, 4.7 kWh per square metre a day. June is the sunniest month (84%) and December the cloudiest (74%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 76% | 2.5 |
| February | 77% | 3.4 |
| March | 79% | 4.6 |
| April | 82% | 6.0 |
| May | 81% | 6.7 |
| June | 84% | 7.3 |
| July | 78% | 6.5 |
| August | 77% | 5.8 |
| September | 82% | 5.1 |
| October | 83% | 4.0 |
| November | 81% | 2.8 |
| December | 74% | 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 much heating and cooling does Ben Lomond need?
A normal year in Ben Lomond brings 2,286 heating degree days, 57% fewer than the median U.S. place (5,373), and 641 cooling degree days, 29% fewer than the median (908). Three months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 3,982 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 434 | 0 |
| February | 339 | 0 |
| March | 294 | 1 |
| April | 207 | 11 |
| May | 112 | 39 |
| June | 30 | 91 |
| July | 6 | 147 |
| August | 4 | 166 |
| September | 17 | 130 |
| October | 95 | 52 |
| November | 290 | 4 |
| December | 457 | 0 |
| Year (annual) | 2,286 | 641 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00040673. 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 Ben Lomond been warmer than normal lately?
2023 averaged 60.3°F, 0.1°F below the 1991-2020 normal of 60.4°F. 2 of the 3 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 60.7°F | +0.3°F | 52.61 |
| 2022 | 61.7°F | +1.3°F | 38.14 |
| 2023 | 60.3°F | −0.1°F | 67.90 |
Over 38 complete years from 1975 to 2022, 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 USC00040673; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Ben Lomond's climate compare?
Ben Lomond is warmer than 102 of the other 218 places with their own NOAA record in California, and wetter than 200. Across the 7,247 U.S. stations with normals, its annual mean of 60.4°F is warmer than 76%.
In the Köppen classification computed from these normals, Ben Lomond 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 Ben Lomond 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.
- Scotts Valley, CA11,828 people · 4 mi SE
- Boulder Creek, CA5,353 people · 4 mi NW
- Felton, CA3,721 people · 3 mi S
- Bonny Doon, CA2,946 people · 4 mi SW
- Brookdale, CA1,308 people · 2 mi NW
- Mount Hermon, CA1,203 people · 3 mi SE
- Lompico, CA1,024 people · 2 mi NE
- Davenport, CA537 people · 8 mi SW
- Zayante, CA366 people · 2 mi E
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 Ben Lomond's climate
What is the coldest month in Ben Lomond?
December, with a normal high of 64°F and a normal low of 37°F. The warmest is August (90°F by day, 51°F at night).
Does it snow in Ben Lomond?
Rarely: NOAA's normal is 0.1 inch a year.
What is the rainiest month in Ben Lomond?
December, with 10.43 in of precipitation in a normal year; the driest is July with 0.01 in.
What plant hardiness zone is Ben Lomond in?
The USDA's 2023 map puts Ben Lomond in zones 9a to 9b across its 2 ZIP code areas (9a in 95005, the largest). By the same method at Ben Lomond's NOAA station, the coldest night of a typical year reaches 24°F (30 years, 1991-2020): zone 9a.
How late can frost come in Ben Lomond?
In half of years the last 32°F night comes after March 25; in one year in ten it comes after April 21. Waiting until April 21 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 Cruz, CA8 miles from this station, 58.7°F a year
- Los Gatos, CA12 miles from this station, 59.7°F a year
- Skyline Ridge Preserve, CA17 miles from this station, 57.1°F a year
- Watsonville, CA19 miles from this station, 57.2°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made