Climate Comfort Score
87/100
Excellent
NOAA 1991–2020 normals 58°F annual avg Public-domain federal data
MT Diablo Junction, CA Climate
Explore average temperature, rainfall, and comfort score sourced from NOAA NCEI's 1991–2020 climate normals →
- 58°F
- Avg annual temp
- 87/100
- Comfort score
- 26.1"
- Annual precip
- 289d
- Growing season
30-year climate normals from 1 weather station (1991-2020).
The climate verdict for MT Diablo Junction
MT Diablo Junction, California averages 58°F a year and scores 87/100 on the comfort index - excellent, milder than 89% of U.S. cities.
- 58°F
- yearly average temperature, NOAA normal
- 87/100
- comfort score, milder than 89% of U.S. cities
- 26.1"
- annual precipitation · 1" snow
- 289 days
- frost-free growing season
Based on NOAA U.S. Climate Normals (1991–2020) - 30-year averages describing the typical year, not a forecast.
Avg Temperature
58°F (15°C)
Avg High
67°F
Avg Low
50°F
Annual Precip
26.1"
Annual Snow
0.7"
Comfort Score
87/100
Excellent
Avg Annual Temperature
58°F
30-year mean (NOAA NCEI)
Annual Precipitation
26.1"
Plus 0.7" of snow
Comfort score vs national 100-point ceiling (MT Diablo Junction) 87.0%
National median (63)
PlainClimate composite, temperature mildness, humidity, precipitation, extreme-weather frequency. Excellent for the MT Diablo Junction area.
How MT Diablo Junction compares to every U.S. city
MT Diablo Junction's comfort score vs. all U.S. cities
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
87 Top 11% higher than 89% of 6,915 US cities
Each bar is a band; taller bars hold more US cities. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source NOAA U.S. Climate Normals, PlainClimate comfort index · 1991–2020
Warming context for MT Diablo Junction
MethodologySince 1900, U.S. land temperatures have tracked (and diverged from) the global mean - the chart below shows how. MT Diablo Junction's current NOAA 1991-2020 normal sits within that longer spread, and the most recent decade runs 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 | 54°F (12°C) | 42°F (5°C) | 48°F (9°C) | 5.1" | 0.1" | 4.3 | 0.0 |
| February | 55°F (13°C) | 42°F (5°C) | 48°F (9°C) | 4.9" | 0.5" | 3.8 | 0.0 |
| March | 58°F (14°C) | 43°F (6°C) | 50°F (10°C) | 3.7" | 0.1" | 2.5 | 0.0 |
| April | 62°F (17°C) | 44°F (7°C) | 53°F (12°C) | 1.9" | 0.0" | 1.8 | 0.0 |
| May | 68°F (20°C) | 49°F (10°C) | 59°F (15°C) | 1.1" | 0.0" | 0.0 | 0.8 |
| June | 76°F (24°C) | 55°F (13°C) | 66°F (19°C) | 0.3" | 0.0" | 0.0 | 3.7 |
| July | 83°F (28°C) | 62°F (16°C) | 72°F (22°C) | 0.0" | 0.0" | 0.0 | 7.5 |
| August | 83°F (28°C) | 61°F (16°C) | 72°F (22°C) | 0.0" | 0.0" | 0.0 | 7.9 |
| September | 80°F (27°C) | 60°F (15°C) | 70°F (21°C) | 0.1" | 0.0" | 0.0 | 5.8 |
| October | 72°F (22°C) | 54°F (12°C) | 63°F (17°C) | 1.2" | 0.0" | 0.0 | 1.3 |
| November | 60°F (16°C) | 46°F (8°C) | 53°F (12°C) | 2.6" | 0.0" | 1.9 | 0.0 |
| December | 53°F (12°C) | 41°F (5°C) | 47°F (9°C) | 5.1" | 0.0" | 4.5 | 0.0 |
Monthly Precipitation
Average monthly rainfall and snowfall
January 5.1"
Snow: 0.1"
11.8 days with precipitation
February 4.9"
Snow: 0.5"
11.1 days with precipitation
March 3.7"
Snow: 0.1"
10.2 days with precipitation
April 1.9"
6.7 days with precipitation
May 1.1"
4.4 days with precipitation
June 0.3"
1.3 days with precipitation
July 0.0"
0.3 days with precipitation
August 0.0"
0.4 days with precipitation
September 0.1"
0.9 days with precipitation
October 1.2"
3.4 days with precipitation
November 2.6"
7.4 days with precipitation
December 5.1"
10.5 days with precipitation
Frost Dates & Growing Season
First Fall Freeze
December 22
50% probability date
Last Spring Freeze
March 8
50% probability date
Growing Season
289 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
3,309
Higher = more heating needed
Cooling Degree Days
925
Higher = more cooling needed
Warmest Month
July
Coldest Month
December
What MT Diablo Junction's climate means for you
MT Diablo Junction runs 58°F a year - peaking in July, coldest in December.
- Gardeners get about 289 frost-free days, with the last spring freeze near March 8 - plan the planting calendar around it, not the regional average.
- Energy bills track 3,309 heating and 925 cooling degree days a year, higher means the furnace or AC runs more.
- Comparing places to live? Line this city up against nearby cities and the national rankings. See rankings
These are 30-year NOAA normals (1991–2020) - the typical year, not a forecast for any specific season.
Climate Guides
Climate Insight: MT Diablo Junction, CA
MT Diablo Junction, California runs an annual average of 58°F, ranging from a mean daily high of 67°F to a mean daily low of 50°F, per NOAA's 1991–2020 climate normals. July is typically the warmest month of the year, while December is the coldest. Drawn from station USC00045915, these thirty-year averages smooth out year-to-year swings into a baseline for what a typical month looks like here.
Anyone planning to live, garden, or travel in MT Diablo Junction should weigh precipitation alongside temperature: the annual average runs 26.1 inches, with 0.7 inches typically falling as snow. The frost-free season averages 289 days, which directly shapes the planting calendar and growing potential for the area, with the last spring freeze near March 8 and the first fall freeze near December 22. And on the energy front, 3,309 heating degree days and 925 cooling degree days tell the story of how often furnaces and air conditioners run during a normal year.
On PlainClimate's composite comfort index, MT Diablo Junction scores 87/100 (Excellent), a blended measure that weighs temperature mildness, precipitation moderation, and extreme-weather frequency against one another. The monthly tables above turn that into a planning tool: expect the mildest highs and lows in the shoulder seasons, July-driven heat at the peak of summer, and December-driven cold at the depth of winter. Every number here is a thirty-year average, not a forecast, so any given year can and does run warmer, cooler, wetter, or drier than the normal.
Frequently Asked Questions
What is the average temperature in MT Diablo Junction, CA? ▼
The average annual temperature in MT Diablo Junction, California is 58°F. The warmest month averages 83°F (28°C) and the coldest averages 41°F (5°C).
How much rain does MT Diablo Junction get? ▼
MT Diablo Junction receives 26.1 inches of precipitation annually, including 0.7 inches of snow. Based on NOAA 30-year climate normals (1991-2020).
What is the comfort score for MT Diablo Junction? ▼
MT Diablo Junction has a climate comfort score of 87/100 (Excellent), milder than 89% of U.S. cities in the PlainClimate database.
When is the growing season in MT Diablo Junction? ▼
MT Diablo Junction has approximately 289 frost-free days per year, with the last spring freeze around March 8 and the first fall freeze around December 22.
How much energy does heating and cooling require in MT Diablo Junction? ▼
MT Diablo Junction has 3,309 heating degree days and 925 cooling degree days annually, a heating-dominated climate. See our <a href="/guides/reading-weather-data/" class="underline hover:text-brand-600">guide to reading weather data</a> for what these figures mean.
Where does this MT Diablo Junction climate data come from? ▼
NOAA U.S. Climate Normals v1.0.1 (1991-2020), from weather station USC00045915 near MT Diablo Junction.
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). Station: USC00045915. 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
Every figure on PlainClimate is rendered directly from NOAA 1991-2020 U.S. Climate Normals data, no number is typed in by an editor. This page draws directly on NOAA 1991-2020 U.S. Climate Normals data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.