Climate Comfort Score
62/100
Good
2026 data Public-data reference. official source
Portola, CA Climate
Temperature, precipitation, and comfort score from NOAA NCEI 1991-2020 normals →
30-year climate normals from 1 weather station (1991-2020).
Portola, California has an average annual temperature of 47°F and a climate comfort score of 62/100 (Good). Annual precipitation totals 23.3", including 37.8" of snow. Based on NOAA 30-year normals (1991–2020).
Avg Temperature
47°F (8°C)
Avg High
63°F
Avg Low
31°F
Annual Precip
23.3"
Annual Snow
37.8"
Comfort Score
62/100
Good
Avg Annual Temperature
47°F
30-year mean (NOAA NCEI)
Annual Precipitation
23.3"
Plus 37.8" of snow
Comfort score vs national 100-point ceiling (Portola) 62.0%
National median (≈55)
PlainClimate composite — temperature mildness, humidity, precipitation, extreme-weather frequency. Good for the Portola area.
Warming context for Portola
MethodologyHow the U.S. land temperature anomaly tracks against the global mean since 1900. The current NOAA 1991-2020 normal for Portola captures average conditions across the spread shown — the most recent decade is warmer than the 30-year mean.
- United States land mean (NOAA NCEI) +0.11 °C/decade
- Global anomaly (NASA GISTEMP) +0.11 °C/decade
- Paris Agreement thresholds 1.5°C / 2.0°C
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Snow | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|---|
| January | 43°F (6°C) | 19°F (-7°C) | 31°F (0°C) | 4.2" | 11.7" | 29.8 | 0.0 |
| February | 46°F (8°C) | 21°F (-6°C) | 34°F (1°C) | 3.9" | 7.6" | 26.6 | 0.0 |
| March | 52°F (11°C) | 25°F (-4°C) | 38°F (4°C) | 3.6" | 6.4" | 27.6 | 0.0 |
| April | 58°F (14°C) | 29°F (-2°C) | 43°F (6°C) | 1.6" | 1.8" | 22.1 | 0.0 |
| May | 67°F (19°C) | 35°F (2°C) | 51°F (11°C) | 1.1" | 0.2" | 11.2 | 0.1 |
| June | 77°F (25°C) | 40°F (5°C) | 59°F (15°C) | 0.5" | 0.0" | 2.6 | 2.1 |
| July | 86°F (30°C) | 45°F (7°C) | 66°F (19°C) | 0.3" | 0.0" | 0.0 | 10.6 |
| August | 85°F (30°C) | 43°F (6°C) | 64°F (18°C) | 0.3" | 0.0" | 0.5 | 7.2 |
| September | 79°F (26°C) | 37°F (3°C) | 58°F (14°C) | 0.4" | 0.1" | 5.6 | 1.6 |
| October | 66°F (19°C) | 30°F (-1°C) | 48°F (9°C) | 1.1" | 0.4" | 22.2 | 0.1 |
| November | 53°F (11°C) | 24°F (-4°C) | 38°F (3°C) | 2.0" | 2.4" | 27.1 | 0.0 |
| December | 42°F (6°C) | 19°F (-7°C) | 31°F (-1°C) | 4.3" | 7.2" | 29.1 | 0.0 |
Monthly Precipitation
Average monthly rainfall and snowfall
January 4.2"
Snow: 11.7"
8.7 days with precipitation
February 3.9"
Snow: 7.6"
8.5 days with precipitation
March 3.6"
Snow: 6.4"
8.1 days with precipitation
April 1.6"
Snow: 1.8"
6.0 days with precipitation
May 1.1"
Snow: 0.2"
5.7 days with precipitation
June 0.5"
2.6 days with precipitation
July 0.3"
1.0 days with precipitation
August 0.3"
1.2 days with precipitation
September 0.4"
Snow: 0.1"
1.8 days with precipitation
October 1.1"
Snow: 0.4"
3.5 days with precipitation
November 2.0"
Snow: 2.4"
6.2 days with precipitation
December 4.3"
Snow: 7.2"
8.4 days with precipitation
Frost Dates & Growing Season
First Fall Freeze
September 10
50% probability date
Last Spring Freeze
June 11
50% probability date
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
6,782
Higher = more heating needed
Cooling Degree Days
144
Higher = more cooling needed
Warmest Month
July
Coldest Month
December
Related Data
PlainEnviro
EPA environmental data — pollution, water quality, and environmental health by location
PlainCarbon
Carbon emissions data — greenhouse gas reporting and facility-level CO2 data
PlainHazard
Natural disaster data — weather-related hazards, FEMA declarations, and risk profiles
PlainAirData
EPA air quality data — AQI readings, pollutant levels, and air quality trends
Climate Guides
Climate Insight: Portola, CA
The NOAA 1991–2020 climate normals describe Portola, California as a location with an annual average temperature of 47°F, ranging from a mean daily high of 63°F to a mean daily low of 31°F. July is typically the warmest month of the year, while December is the coldest. These thirty-year averages, computed from station USC00047085, smooth out year-to-year variability and give a baseline expectation for typical conditions in any given month.
Precipitation patterns matter as much as temperature for anyone planning to live, garden, or travel here. Portola receives roughly 23.3 inches of precipitation each year, with 37.8 inches typically falling as snow. Growing-season length varies with elevation and microclimate, with the last spring freeze near June 11 and the first fall freeze near September 10. For energy use, 6,782 heating degree days and 144 cooling degree days tell the story of how often furnaces and air conditioners run during a normal year.
On PlainClimate's composite comfort index, Portola scores 62/100 (Good), a blended measure that weighs temperature mildness, precipitation moderation, and extreme-weather frequency against one another. Use the monthly tables above to plan around specific windows — shoulder seasons for mild highs and lows, peak summer for July-driven heat, or deep winter for December-driven cold. All figures here are thirty-year averages: any single year may run warmer, wetter, drier, or cooler than the normal, so treat them as planning guidance rather than forecasts.
Frequently Asked Questions
What is the average temperature in Portola, CA? ▼
The average annual temperature in Portola, California is 47°F. The warmest month averages 86°F (30°C) and the coldest averages 19°F (-7°C).
How much rain does Portola get? ▼
Portola receives 23.3 inches of precipitation annually, including 37.8 inches of snow. Based on NOAA 30-year climate normals (1991-2020).
What is the comfort score for Portola? ▼
Portola has a climate comfort score of 62/100 (Good). This score considers temperature mildness, humidity, precipitation, and extreme weather frequency.
When is the growing season in Portola? ▼
Growing season data is not available for Portola.
How much energy does heating and cooling require in Portola? ▼
Portola has 6,782 heating degree days and 144 cooling degree days annually. Higher heating degree days indicate greater winter energy demand, while higher cooling degree days indicate greater summer cooling needs.
Where does this Portola climate data come from? ▼
All climate data comes from NOAA U.S. Climate Normals v1.0.1, covering the 30-year period from 1991 to 2020. Data is collected from weather station USC00047085. These 30-year averages are the standard reference for typical weather conditions.
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). Station: USC00047085. For informational purposes only.
Read our methodology — how this data is sourced, computed, and verified.
Related
Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainClimate Editorial
