Climate Comfort Score
37/100
Below Average
2026 data Public-data reference. official source
Port San Juan, AK Climate
Temperature, precipitation, and comfort score from NOAA NCEI 1991-2020 normals →
30-year climate normals from 1 weather station (1991-2020).
Port San Juan, Alaska has an average annual temperature of 41°F and a climate comfort score of 37/100 (Below Average). Annual precipitation totals 137.9". Based on NOAA 30-year normals (1991–2020).
Avg Temperature
41°F (5°C)
Avg High
46°F
Avg Low
36°F
Annual Precip
137.9"
Comfort Score
37/100
Below Average
Avg Annual Temperature
41°F
30-year mean (NOAA NCEI)
Annual Precipitation
137.9"
Liquid-equivalent total
Comfort score vs national 100-point ceiling (Port San Juan) 37.0%
National median (≈55)
PlainClimate composite — temperature mildness, humidity, precipitation, extreme-weather frequency. Below Average for the Port San Juan area.
Warming context for Port San Juan
MethodologyHow the U.S. land temperature anomaly tracks against the global mean since 1900. The current NOAA 1991-2020 normal for Port San Juan 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 | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|
| January | 34°F (1°C) | 26°F (-3°C) | 30°F (-1°C) | 12.3" | 23.2 | 0.0 |
| February | 35°F (2°C) | 26°F (-3°C) | 31°F (-1°C) | 11.6" | 20.7 | 0.0 |
| March | 36°F (2°C) | 26°F (-3°C) | 31°F (0°C) | 9.6" | 24.3 | 0.0 |
| April | 43°F (6°C) | 32°F (0°C) | 37°F (3°C) | 10.3" | 14.7 | 0.0 |
| May | 52°F (11°C) | 37°F (3°C) | 45°F (7°C) | 8.1" | 3.3 | 0.0 |
| June | 59°F (15°C) | 44°F (7°C) | 52°F (11°C) | 4.5" | 0.1 | 0.0 |
| July | 63°F (17°C) | 50°F (10°C) | 56°F (13°C) | 5.3" | 0.0 | 0.0 |
| August | 61°F (16°C) | 49°F (10°C) | 55°F (13°C) | 9.8" | 0.0 | 0.0 |
| September | 54°F (12°C) | 44°F (6°C) | 49°F (9°C) | 17.4" | 0.6 | 0.0 |
| October | 45°F (7°C) | 36°F (2°C) | 41°F (5°C) | 17.3" | 7.9 | 0.0 |
| November | 38°F (3°C) | 30°F (-1°C) | 34°F (1°C) | 15.9" | 18.7 | 0.0 |
| December | 36°F (2°C) | 28°F (-2°C) | 32°F (0°C) | 15.8" | 22.1 | 0.0 |
Monthly Precipitation
Average monthly rainfall
January 12.3"
20.0 days with precipitation
February 11.6"
18.0 days with precipitation
March 9.6"
17.3 days with precipitation
April 10.3"
17.7 days with precipitation
May 8.1"
15.7 days with precipitation
June 4.5"
13.7 days with precipitation
July 5.3"
15.2 days with precipitation
August 9.8"
16.3 days with precipitation
September 17.4"
19.9 days with precipitation
October 17.3"
20.7 days with precipitation
November 15.9"
19.1 days with precipitation
December 15.8"
22.0 days with precipitation
Frost Dates & Growing Season
First Fall Freeze
October 7
50% probability date
Last Spring Freeze
May 10
50% probability date
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
8,759
Higher = more heating needed
Cooling Degree Days
1
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
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
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PlainAirData
EPA air quality data — AQI readings, pollutant levels, and air quality trends
Climate Guides
Climate Insight: Port San Juan, AK
The NOAA 1991–2020 climate normals describe Port San Juan, Alaska as a location with an annual average temperature of 41°F, ranging from a mean daily high of 46°F to a mean daily low of 36°F. July is typically the warmest month of the year, while January is the coldest. These thirty-year averages, computed from station USC00507738, 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. Port San Juan receives roughly 137.9 inches of precipitation each year, predominantly as rainfall. Growing-season length varies with elevation and microclimate, with the last spring freeze near May 10 and the first fall freeze near October 7. For energy use, 8,759 heating degree days and 1 cooling degree days tell the story of how often furnaces and air conditioners run during a normal year.
On PlainClimate's composite comfort index, Port San Juan scores 37/100 (Below Average), 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 January-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 Port San Juan, AK? ▼
The average annual temperature in Port San Juan, Alaska is 41°F. The warmest month averages 63°F (17°C) and the coldest averages 26°F (-3°C).
How much rain does Port San Juan get? ▼
Port San Juan receives 137.9 inches of precipitation annually. Based on NOAA 30-year climate normals (1991-2020).
What is the comfort score for Port San Juan? ▼
Port San Juan has a climate comfort score of 37/100 (Below Average). This score considers temperature mildness, humidity, precipitation, and extreme weather frequency.
When is the growing season in Port San Juan? ▼
Growing season data is not available for Port San Juan.
How much energy does heating and cooling require in Port San Juan? ▼
Port San Juan has 8,759 heating degree days and 1 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 Port San Juan 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 USC00507738. 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: USC00507738. 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
