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Climate · Rancho San Diego

Rancho San Diego, CA climate

Rancho San Diego has warm winters and warm summers, with very little rain. A typical July afternoon reaches 86°, a January night drops to 43°, and snow is almost unheard of.

NOAA 1991-2020 climate normals Updated once a decade
July high
86°
580th coolest of 1,618 California towns
January low
43°
380th mildest of 1,618 California towns
Rain + melted snow
12 in
445th driest of 1,618 California towns
Snow a winter
0.0 in
470th snowiest of 1,499 California towns
+19°

19° warmer than normal today. The forecast high is 103°, and a typical Oct 2 in Rancho San Diego peaks around 84°.Live forecast: National Weather Service · Normal: NOAA 1991–2020

A normal year

What a year in Rancho San Diego feels like

Winter

69° / 43°
Typical high / low · Snow is rare

Spring

74° / 50°
Typical high / low · Frost is rare by spring

Summer

85° / 61°
Typical high / low · 57 days reach 90° in a normal year

Fall

81° / 54°
Typical high / low · Mild well into the fall
Best months to be outsideJanFebMarAprMayJunOctNovDecHighs of 62–84° and lows of 40° or more
Month by month

Rancho San Diego weather by month

Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.

MonthHighLowRain + meltSnowWet daysSnow on ground30-yr range
January69°43°2.5" 060 52° – 61°
February69°44°2.8" 070 53° – 62°
March71°47°2.0" 050 54° – 65°
April74°49°1.0" 040 58° – 66°
May76°54°0.4" 020 61° – 70°
June81°58°0.1" 010 65° – 74°
July86°62°0.0" 010 70° – 79°
August89°63°0.0" 000 72° – 79°
September87°60°0.1" 010 70° – 78°
October81°54°0.5" 020 64° – 72°
November75°47°1.1" 030 54° – 64°
December68°42°2.0" 060 52° – 59°
Year77°52°12.4"0.0"360

“Wet days” have at least 0.01" of rain or melted snow. “Snow on ground” counts days with 1" or more. The 30-year range is the coldest and warmest that month’s average temperature got between 1991 and 2020.

Rain & snow

Rain and snow in Rancho San Diego

Rancho San Diego gets 12 inches of rain and melted snow a year. February is the wettest month and July the driest. Rain or snow falls on about 36 days a year.

12 in
Rain + melted snow a year
Less rain than 96% of U.S. towns
0.0 in
Snow in a normal winter
Less snow than 96% of U.S. towns
0 days
With 1"+ of snow on the ground
Fewer than 94% of U.S. towns

Rain + melted snow by month

Inches of water
2.8"

Snowfall by month

No measurable snow in a normal year.
Frost & the growing season

A year-round growing season

🌿 Only about most winters dip to 32° here (73% of years), so gardens can grow year-round.
3
nights at or below 32° in a normal year
0
nights below 0° in a normal year
57
days that reach 90° in a normal year

Freezing nights by month

Average nights at or below 32°

90° days by month

Average days at 90° or more
Heating & cooling

Heating and cooling a home in Rancho San Diego

Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Rancho San Diego, 49% of that work is heating and 51% is cooling.

49%heating
1,309 heating degree daysLess heating than 96% of U.S. towns
1,377 cooling degree daysMore cooling than 75% of U.S. towns

Degree days measure how far each day’s average temperature falls below or rises above 65°, added up over a year. Source: NOAA station normals.

Around Rancho San Diego

Rancho San Diego and its neighbors

Rancho San Diego borders 6 towns with climate data. January nights across them vary by 2.5°. Granite Hills has the coldest January nights (42°) and Crest the hottest July afternoons (89°). Rancho San Diego’s January low is 43° and its July high 86°.

Bostonia: January low 42°, July high 87°La Mesa: January low 44°, July high 83°Santee: January low 42°, July high 86°Winter Gardens: January low 42°, July high 88°San Diego: January low 45°, July high 80°La Presa: January low 45°, July high 82°Lemon Grove: January low 45°, July high 82°Harbison Canyon: January low 42°, July high 89°El Cajon: January low 43°, July high 85°Casa de Oro-Mount Helix: January low 44°, July high 85°Jamul: January low 42°, July high 88°Spring Valley: January low 44°, July high 84°Granite Hills: January low 42°, July high 88°Crest: January low 42°, July high 89°Rancho San Diego: January low 43°, July high 86° Rancho San DiegoEl CajonCasa de Oro-Mount HelixJamulSpring ValleyGranite HillsCrest
ColderMilder42° to 45°
Granite Hills41.5° −1.2°
Crest41.5° −1.2°
Jamul42.4° −0.3°
Rancho San Diego42.7°
El Cajon42.7° same
Casa de Oro-Mount Helix43.5° +0.8°
Spring Valley44.0° +1.3°

Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.

Compared with other towns

How Rancho San Diego compares

Summer heat86° July high
Hotter than 59% of U.S. towns580th coolest of 1,618 California towns
Winter cold43° January low
Milder than 96% of U.S. towns380th mildest of 1,618 California towns
Precipitation12" a year
Drier than 96% of U.S. towns445th driest of 1,618 California towns
Snow0.0" a winter
Less snow than 96% of U.S. towns470th snowiest of 1,499 California towns
California climate rankings towns with 2,500+ residents#258Mildest winters of 753#285Coolest summers of 753#469Hottest summers of 753#519Wettest of 753All CA rankings →

Compared with every U.S. town and city on TownTapestry, each counted once.

Then and now

Warmer than it used to be

+2.2°1991–2020 average vs. the 20th century (1901–2000)

The last 30 years in Rancho San Diego averaged 2.2° warmer than the 1900s. The biggest change is in January (+3.2°). The shift is larger than in 97% of U.S. towns.

❄️ Winter+2.3° now 56°, was 54°
🌷 Spring+2.2° now 62°, was 60°
☀️ Summer+1.9° now 73°, was 71°
🍂 Fall+2.3° now 67°, was 65°

Change by month1991–2020 average minus 1901–2000 average, at Rancho San Diego’s spot on NOAA’s grid

Year to year

How much a month can swing

A normal is an average, and real years wander around it. March swings the most: between 1991 and 2020 its average temperature ranged from 54° to 65°. August is the most reliable, staying within 6°.

Coldest to warmest month in 30 yearsNormal
Questions

Common questions about Rancho San Diego’s climate

What is the coldest month in Rancho San Diego?

December, with a typical high of 68° and a low of 42°.

What is the hottest month in Rancho San Diego?

August, with a typical high of 89° and a low of 63°. About 57 days a year reach 90°.

How much snow does Rancho San Diego get?

Almost none. A normal year brings 0.0 inches.

When is the first frost in Rancho San Diego?

Frost is uncommon. Only 73% of years see a night at 32° or below.

What is the rainiest month in Rancho San Diego?

February, with 2.8 inches of rain and melted snow. The year totals 12 inches.

Temperatures and rainfall come from NOAA’s gridded climate normals for Rancho San Diego itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at El Cajon, CA (3 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.

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