Pasadena, California climate: Normal weather by month, frost dates and records
Pasadena's normal year runs from 45°F December nights to 91°F August afternoons, with 20.1 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 18.9°C, December lows of 7°C, August highs of 33°C, 510 mm of precipitation a year.
- NOAA stationPasadena
- Station IDUSC00046719
- Location34.15°N 118.14°W
- Elevation864 ft (263 m)
- From the centerunder 1 mile
- Population137,195
On October 23, the normal high in Pasadena is 82°F and the normal low 55°F, and the chance of measurable rain or snow is 9%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Pasadena.
- Jan 68° 46°
- Feb 69° 46°
- Mar 73° 48°
- Apr 76° 51°
- May 78° 54°
- Jun 84° 58°
- Jul 89° 62°
- Aug 91° 63°
- Sep 90° 62°
- Oct 83° 56°
- Nov 75° 50°
- Dec 67° 45°
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 Pasadena each month?
August is the warmest month, with normal highs of 91°F; December the coldest, with normal lows of 45°F. The most precipitation falls in February (5.16 in), the least in August (0.03 in).
Each month has its own page with the day-by-day normals, the month's records and its recent years:
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 68°F | 46°F | 56.8°F | 4.51 | 7 | <1 | <1 | 10 h 10 min |
| February | 69°F | 46°F | 57.7°F | 5.16 | 8 | <1 | <1 | 11 h |
| March | 73°F | 48°F | 60.5°F | 3.03 | 6 | 1 | <1 | 11 h 50 min |
| April | 76°F | 51°F | 63.4°F | 1.11 | 3 | 3 | <1 | 13 h |
| May | 78°F | 54°F | 66.1°F | 0.48 | 3 | 3 | <1 | 13 h 50 min |
| June | 84°F | 58°F | 70.7°F | 0.21 | 2 | 6 | <1 | 14 h 30 min |
| July | 89°F | 62°F | 75.6°F | 0.06 | 1 | 15 | <1 | 14 h 10 min |
| August | 91°F | 63°F | 77.2°F | 0.03 | <1 | 19 | <1 | 13 h 30 min |
| September | 90°F | 62°F | 75.8°F | 0.22 | 1 | 16 | <1 | 12 h 30 min |
| October | 83°F | 56°F | 69.7°F | 0.84 | 3 | 8 | <1 | 11 h 20 min |
| November | 75°F | 50°F | 62.1°F | 1.10 | 3 | 2 | <1 | 10 h 20 min |
| December | 67°F | 45°F | 56.0°F | 3.33 | 6 | <1 | <1 | 9 h 50 min |
| Year (annual) | 79°F | 53°F | 66.0°F | 20.08 | 43 | 74 | <1 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 20°C | 8°C | 13.8°C | 115 mm |
| February | 21°C | 8°C | 14.3°C | 131 mm |
| March | 23°C | 9°C | 15.8°C | 77 mm |
| April | 25°C | 10°C | 17.4°C | 28 mm |
| May | 26°C | 12°C | 18.9°C | 12 mm |
| June | 29°C | 14°C | 21.5°C | 5 mm |
| July | 32°C | 17°C | 24.2°C | 2 mm |
| August | 33°C | 17°C | 25.1°C | 1 mm |
| September | 32°C | 16°C | 24.3°C | 6 mm |
| October | 28°C | 13°C | 20.9°C | 21 mm |
| November | 24°C | 10°C | 16.7°C | 28 mm |
| December | 20°C | 7°C | 13.3°C | 85 mm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00046719; 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 Pasadena?
Normal highs sit between 65°F and 85°F in January, February, March, April, May, June, October, November and December. Of those, June has the fewest days with rain (2).
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 USC00046719.
When is the last frost in Pasadena?
A night at 32°F or colder comes in only 13% of years in Pasadena (NOAA). NOAA's median date of the last spring frost is January 8 and of the first autumn frost January 7.
NOAA puts the median frost-free season at 365 days, and the season without a hard freeze (28°F) at 365 days.
The USDA's 2023 Plant Hardiness Zone Map puts Pasadena in zones 10a to 10b across its 6 ZIP code areas (10a in 91107, the largest). By the map's own method, the average of each year's coldest night over 1991-2020, Pasadena's NOAA station is in zone 10b: the coldest night of a typical year reaches 36°F (26 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 USC00046719; 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 Pasadena ZIP code in?
The USDA's 2023 map gives each ZIP code area one zone. Pasadena's 6 ZIP code areas run from zone 10a to 10b: 5 in 10a and 1 in 10b. 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 Pasadena?
In a normal year in Pasadena, 74 days a year reach 90°F (10 of them 100°F or more), nights almost never fall to freezing and 43 days bring measurable precipitation.
- Days at 90°F or more
- 74a normal year
- Days at 100°F or more
- 10a normal year
- Nights at 32°F or colder
- fewer than 1a normal year
- Days that stay below freezing
- fewer than 1high of 32°F or less
- Days with 0.01 inch of precipitation
- 43a normal year
The highest temperature in this station's record (since 1893) is 115°F, on September 6, 2020; the lowest is 21°F, on January 7, 1913.
The wettest calendar year on that record is 1983, with 48.47 in; the snowiest season is 1948–49, with 3.0 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00046719; records: ACIS (NOAA Regional Climate Centers), station USC00046719. Records use complete months only; a month missing more than three days is left out.
How sunny is Pasadena?
Over a year 90% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Pasadena, 5.7 kWh per square metre a day. August is the sunniest month (97%) and February the cloudiest (82%). Among the 459 U.S. places of 50,000 or more, that ranks tied 21st (with 17 others) in sunshine.
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 83% | 3.2 |
| February | 82% | 4.0 |
| March | 85% | 5.4 |
| April | 87% | 6.7 |
| May | 89% | 7.5 |
| June | 93% | 8.1 |
| July | 95% | 7.9 |
| August | 97% | 7.5 |
| September | 95% | 6.3 |
| October | 91% | 4.8 |
| November | 88% | 3.6 |
| December | 83% | 2.9 |
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 Pasadena need?
A normal year in Pasadena brings 1,236 heating degree days, 77% fewer than the median U.S. place (5,373), and 1,604 cooling degree days, 77% more than the median (908). No month reaches 300 heating degree days. For gardens and crops, NOAA counts 5,867 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 261 | 7 |
| February | 216 | 12 |
| March | 164 | 25 |
| April | 100 | 52 |
| May | 53 | 87 |
| June | 7 | 180 |
| July | 0 | 327 |
| August | 0 | 380 |
| September | 2 | 324 |
| October | 23 | 167 |
| November | 127 | 42 |
| December | 283 | 3 |
| Year (annual) | 1,236 | 1,604 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00046719. 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 Pasadena been warmer than normal lately?
2025 averaged 67.6°F, 1.6°F above the 1991-2020 normal of 66.0°F. 5 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 68.3°F | +2.3°F | 15.18 |
| 2022 | 69.6°F | +3.6°F | 13.97 |
| 2023 | 66.5°F | +0.5°F | 42.17 |
| 2024 | 67.4°F | +1.4°F | 22.61 |
| 2025 | 67.6°F | +1.6°F | 24.07 |
Over 84 complete years from 1909 to 2025, the station's annual mean temperature rose at a fitted 6.0°F per century (+0.33°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00046719; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Pasadena's climate compare?
Pasadena is warmer than 195 of the other 218 places with their own NOAA record in California, and wetter than 136. Across the 7,247 U.S. stations with normals, its annual mean of 66.0°F is warmer than 90%.
In the Köppen classification computed from these normals, Pasadena 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 Pasadena share this climate record?
6 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.
- Glendale, CAalso near: Burbank (7 mi, 65.2°F a year); Los Angeles (9 mi, 65.8°F a year)187,823 people · 6 mi W
- Altadena, CA41,921 people · 3 mi N
- South Pasadena, CA25,656 people · 3 mi S
- La Cañada Flintridge, CA19,621 people · 5 mi NW
- San Marino, CA12,105 people · 3 mi SE
- San Pasqual, CA2,014 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 Pasadena's climate
What is the coldest month in Pasadena?
December, with a normal high of 67°F and a normal low of 45°F. The warmest is August (91°F by day, 63°F at night).
Does it snow in Pasadena?
Rarely: NOAA's normal is no measurable snow a year.
What is the rainiest month in Pasadena?
February, with 5.16 in of precipitation in a normal year; the driest is August with 0.03 in.
What plant hardiness zone is Pasadena in?
The USDA's 2023 map puts Pasadena in zones 10a to 10b across its 6 ZIP code areas (10a in 91107, the largest). By the same method at Pasadena's NOAA station, the coldest night of a typical year reaches 36°F (26 years, 1991-2020): zone 10b.
Nearby and next
- Pasadena in OctoberThis month day by day, its records and recent years
- California climateThe statewide normals and every place in the state
- San Gabriel, CA5 miles from this station, 66.0°F a year
- Mount Wilson CBS, CA7 miles from this station, 58.4°F a year
- Los Angeles, CA9 miles from this station, 65.8°F a year
- Burbank, CA12 miles from this station, 65.2°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made