San Luis Obispo Poly, California climate: Climate normals at a NOAA weather station
San Luis Obispo Poly's normal year runs from 44°F December nights to 80°F August afternoons, with 22.4 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 15.8°C, December lows of 7°C, August highs of 27°C, 569 mm of precipitation a year.
- NOAA stationSan Luis Obispo Poly
- Station IDUSC00047851
- Location35.31°N 120.66°W
- Elevation308 ft (94 m)
On October 23, the normal high in San Luis Obispo Poly is 77°F and the normal low 51°F, and the chance of measurable rain or snow is 11%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for San Luis Obispo Poly.
- Jan 65° 44°
- Feb 65° 44°
- Mar 67° 46°
- Apr 69° 47°
- May 72° 49°
- Jun 76° 52°
- Jul 78° 54°
- Aug 80° 55°
- Sep 80° 54°
- Oct 78° 52°
- Nov 71° 47°
- Dec 64° 44°
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 San Luis Obispo Poly each month?
August is the warmest month, with normal highs of 80°F; December the coldest, with normal lows of 44°F. The most precipitation falls in January (5.07 in), the least in August (0.01 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 65°F | 44°F | 54.4°F | 5.07 | 9 | <1 | 1 | 10 h |
| February | 65°F | 44°F | 54.8°F | 4.92 | 10 | <1 | 1 | 10 h 50 min |
| March | 67°F | 46°F | 56.7°F | 3.89 | 9 | <1 | <1 | 11 h 50 min |
| April | 69°F | 47°F | 58.0°F | 1.38 | 4 | 1 | <1 | 13 h |
| May | 72°F | 49°F | 60.6°F | 0.51 | 2 | 1 | <1 | 14 h |
| June | 76°F | 52°F | 63.8°F | 0.13 | 1 | 2 | <1 | 14 h 30 min |
| July | 78°F | 54°F | 66.3°F | 0.07 | 1 | 2 | <1 | 14 h 20 min |
| August | 80°F | 55°F | 67.3°F | 0.01 | <1 | 3 | <1 | 13 h 30 min |
| September | 80°F | 54°F | 67.0°F | 0.11 | 1 | 4 | <1 | 12 h 30 min |
| October | 78°F | 52°F | 64.7°F | 0.76 | 3 | 5 | <1 | 11 h 20 min |
| November | 71°F | 47°F | 59.1°F | 1.98 | 4 | <1 | <1 | 10 h 20 min |
| December | 64°F | 44°F | 54.0°F | 3.59 | 8 | <1 | 1 | 9 h 50 min |
| Year (annual) | 72°F | 49°F | 60.5°F | 22.42 | 52 | 19 | 3 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 18°C | 7°C | 12.4°C | 129 mm |
| February | 18°C | 7°C | 12.7°C | 125 mm |
| March | 20°C | 8°C | 13.7°C | 99 mm |
| April | 21°C | 8°C | 14.4°C | 35 mm |
| May | 22°C | 10°C | 15.9°C | 13 mm |
| June | 24°C | 11°C | 17.7°C | 3 mm |
| July | 26°C | 12°C | 19.1°C | 2 mm |
| August | 27°C | 13°C | 19.6°C | 0 mm |
| September | 27°C | 12°C | 19.4°C | 3 mm |
| October | 25°C | 11°C | 18.2°C | 19 mm |
| November | 22°C | 9°C | 15.1°C | 50 mm |
| December | 18°C | 7°C | 12.2°C | 91 mm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00047851; 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 San Luis Obispo Poly?
Normal highs sit between 65°F and 85°F in February, March, April, May, June, July, August, September, October and November. Of those, August 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 USC00047851.
When is the last frost at San Luis Obispo Poly?
In San Luis Obispo Poly, the last spring frost (32°F) comes after January 16 in half of years and after February 26 in one year in ten; the first autumn frost comes before December 25 in half of years and before November 25 in one year in ten. A night at 32°F or colder comes at all in 68% of years here (NOAA).
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- January 161 year in 10 after February 26; 9 in 10 after December 11
- First autumn frost, half of years before
- December 251 year in 10 before November 25; 9 in 10 before February 12
NOAA puts the median frost-free season at 349 days, and the season without a hard freeze (28°F) at 365 days.
A hard freeze (28°F) comes after January 9 in half of springs and before January 6 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts San Luis Obispo Poly in zone 9b in ZIP code 93410, 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 10a: the coldest night of a typical year reaches 31°F (21 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 USC00047851; 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 San Luis Obispo Poly?
In a normal year in San Luis Obispo Poly, 19 days a year reach 90°F (2 of them 100°F or more), 3 nights fall to 32°F or colder and 52 days bring measurable precipitation.
- Days at 90°F or more
- 19a normal year
- Days at 100°F or more
- 2a normal year
- Nights at 32°F or colder
- 3a normal year
- Days that stay below freezing
- fewer than 1high of 32°F or less
- Days with 0.01 inch of precipitation
- 52a normal year
The highest temperature in this station's record (since 1927) is 113°F, on September 6, 2020; the lowest is 17°F, on December 23, 1990.
The wettest calendar year on that record is 1969, with 48.76 in.
Source: NOAA NCEI 1991-2020 annual normals, station USC00047851; records: ACIS (NOAA Regional Climate Centers), station USC00047851. Records use complete months only; a month missing more than three days is left out.
How sunny is it at San Luis Obispo Poly?
Over a year 90% of the sunlight that would reach the ground under clear skies gets through the clouds at San Luis Obispo Poly, 5.5 kWh per square metre a day. June is the sunniest month (95%) and December the cloudiest (80%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 81% | 2.9 |
| February | 81% | 3.8 |
| March | 84% | 5.2 |
| April | 87% | 6.6 |
| May | 91% | 7.7 |
| June | 95% | 8.3 |
| July | 94% | 8.0 |
| August | 95% | 7.3 |
| September | 95% | 6.2 |
| October | 91% | 4.6 |
| November | 86% | 3.3 |
| December | 80% | 2.6 |
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 San Luis Obispo Poly record?
A normal year at San Luis Obispo Poly brings 2,031 heating degree days, 62% fewer than the median U.S. place (5,373), and 418 cooling degree days, 54% fewer than the median (908). Two months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 3,929 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 329 | 2 |
| February | 289 | 4 |
| March | 264 | 6 |
| April | 221 | 12 |
| May | 158 | 22 |
| June | 76 | 39 |
| July | 28 | 67 |
| August | 17 | 86 |
| September | 31 | 90 |
| October | 82 | 71 |
| November | 196 | 19 |
| December | 341 | 1 |
| Year (annual) | 2,031 | 418 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00047851. 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 San Luis Obispo Poly been warmer than normal?
2025 averaged 61.5°F, 1.0°F above the 1991-2020 normal of 60.5°F. 4 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 60.9°F | +0.4°F | 23.87 |
| 2022 | 61.5°F | +1.0°F | 16.44 |
| 2023 | 60.3°F | −0.2°F | 40.93 |
| 2024 | 61.0°F | +0.5°F | 23.10 |
| 2025 | 61.5°F | +1.0°F | 25.30 |
Over 103 complete years from 1896 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 USC00047851; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does San Luis Obispo Poly's climate compare?
San Luis Obispo Poly is warmer than 103 of the 219 places with their own NOAA record in California, and wetter than 147. Across the 7,247 U.S. stations with normals, its annual mean of 60.5°F is warmer than 76%.
In the Köppen classification computed from these normals, San Luis Obispo Poly 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 San Luis Obispo Poly share this climate record?
3 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.
- California Polytechnic State University, CA7,529 people · 0 mi W
- Santa Margarita, CA665 people · 7 mi NE
- Garden Farms, CA248 people · 8 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 San Luis Obispo Poly's climate
What is the coldest month at San Luis Obispo Poly?
December, with a normal high of 64°F and a normal low of 44°F. The warmest is August (80°F by day, 55°F at night).
Does it snow at San Luis Obispo Poly?
Rarely: NOAA's normal is no measurable snow a year.
What is the rainiest month at San Luis Obispo Poly?
January, with 5.07 in of precipitation in a normal year; the driest is August with 0.01 in.
What plant hardiness zone is San Luis Obispo Poly in?
The USDA's 2023 map puts San Luis Obispo Poly in zone 9b in ZIP code 93410, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches 31°F (21 years, 1991-2020): zone 10a.
How late can frost come at San Luis Obispo Poly?
In half of years the last 32°F night comes after January 16; in one year in ten it comes after February 26. Waiting until February 26 leaves about a one-in-ten chance of a later frost.
Nearby and next
- California climateThe statewide normals and every place in the state
- San Luis Obispo, CA5 miles from this station, 59.7°F a year
- Pismo Beach, CA10 miles from this station, 59.1°F a year
- Morro Bay, CA11 miles from this station, 59.5°F a year
- Paso Robles, CA25 miles from this station, 60.0°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made