Mount Wilson (California)

Mountain Southern California peak hosting historic Mount Wilson Observatory

In the San Gabriel Mountains, Mount Wilson hosts an astronomical observatory and communication towers; hikers use established trails for day trips and sunrise photography.

Main image

Mount Wilson is a mountain in the San Gabriel Mountains of California, located in Los Angeles County and famous for the Mount Wilson Observatory. The site is historically significant in astronomy because of the large telescopes sited there and discoveries made using them.

The summit area contains an observatory complex with telescope domes, service buildings and a visitor area; the site has interpretive exhibits and limited public visiting hours. The observatory houses several historic instruments that played major roles in early 20th-century astronomy.

The observatory was established in the early 20th century and developed over decades as a center for optical astronomy; it has continued scientific and public functions while the surrounding mountain forests and fire roads have been managed for recreation and research support.

Geographically Mount Wilson rises in the San Gabriel range about 20 kilometers northeast of central Los Angeles and sits above the communities of Pasadena and the San Gabriel Valley. The summit is reachable by paved mountain roads and is a well-known vantage point for views across the Los Angeles Basin.

  • Historic telescopes: Home to the Mount Wilson Observatory and historically important telescopes including the 100-inch Hooker telescope used in landmark astronomical work in the early 20th century.
  • Proximity to Los Angeles: Situated about 20 kilometers northeast of downtown Los Angeles, the summit provides panoramic views over the Los Angeles Basin and is reachable by paved mountain roads from Pasadena and neighboring communities.

What to See #

  • Mount Wilson Observatory: A collection of observing facilities and visitor areas built along the summit ridge; the observatory complex includes historic telescope houses and a visitor center with exhibits about astronomy and the site's scientific history.
Mount Wilson (California)
San Gabriel Mountains, Los Angeles County, California, USA (approx. 34.2239°N, 118.0612°W)
34.2239, -118.0612

How to Get to Mount Wilson (California) #

Drive from La Cañada Flintridge or the Pasadena area via Mount Wilson Road (County Route N3). The paved road is steep and winding; follow posted signs to the Mount Wilson Observatory. Public transit is limited; many visitors use private vehicles or guided tours.

Tips for Visiting Mount Wilson (California) #

  • If visiting the Mount Wilson Observatory, check the observatory website for public tour hours and special event nights - the mountain itself has gated roads at times.
  • Drive Mount Wilson Road from La Cañada Flintridge; road is narrow and steep-larger vehicles should use caution.
  • Bring warm layers even on summer evenings-the elevation and clear skies make nights chill fast.

Best Time to Visit Mount Wilson (California) #

Late spring through fall provides the most reliable weather; visitors to the observatory should check its public schedule for tours and events.

Spring-Fall
March-October · 5°C to 25°C
Most comfortable weather for driving and visiting the observatory; clear days offer long-distance views.
Winter
December-February · 0°C to 10°C
Occasional snow at the summit and colder nights; roads can be icy after storms.

Weather & Climate near Mount Wilson (California) #

Climate

Mount Wilson (California)'s climate is classified as Warm-Summer Mediterranean - Warm-Summer Mediterranean climate with warm summers (peaking in August) and cold winters (coldest in February). Temperatures range from 3°C to 29°C. Moderate rainfall (733 mm/year) with a pronounced dry season.

Temperature & Rainfall
Temperature Range
29°
Warmest Month
Coldest Month
Monthly Conditions

January

January is cold with highs of 12°C and lows of 3°C. Significant rainfall (137 mm).

Comfort

Feels Like Cold
C
Temperature
12°

Weather

137 mm
Rainfall
3.7 m/s
Wind
Light Breeze

February

February is the coolest month with highs of 12°C and lows of 3°C. The wettest month with heavy rain (141 mm).

Comfort

Feels Like Cold
C
Temperature
12°

Weather

141 mm
Rainfall
3.9 m/s
Wind
Light Breeze

March

March is cold with highs of 13°C and lows of 3°C. Significant rainfall (121 mm).

Comfort

Feels Like Cold
C
Temperature
13°

Weather

121 mm
Rainfall
3.8 m/s
Wind
Light Breeze

April

April is cool with highs of 16°C and lows of 4°C. Moderate rainfall (64 mm).

Comfort

10°
Feels Like Cool
10°C
Temperature
16°

Weather

64 mm
Rainfall
4.1 m/s
Wind
Light Breeze

May

May is cool with highs of 19°C and lows of 8°C. Light rainfall.

Comfort

13°
Feels Like Cool
13°C
Temperature
19°

Weather

16 mm
Rainfall
3.8 m/s
Wind
Light Breeze

June

June is cool with highs of 24°C and lows of 12°C. Almost no rain.

Comfort

18°
Feels Like Cool
18°C
Temperature
12° 24°

Weather

3 mm
Rainfall
3.5 m/s
Wind
Light Breeze

July

July is mild with highs of 28°C and lows of 16°C. The driest month with just 2 mm.

Comfort

22°
Feels Like Mild
22°C
Temperature
16° 28°

Weather

2 mm
Rainfall
3.1 m/s
Wind
Light Breeze

August

August is the warmest month with highs of 29°C and lows of 17°C. Almost no rain.

Comfort

23°
Feels Like Mild
23°C
Temperature
17° 29°

Weather

8 mm
Rainfall
3.0 m/s
Wind
Light Breeze

September

September is mild with highs of 26°C and lows of 15°C. Light rainfall.

Comfort

21°
Feels Like Mild
21°C
Temperature
15° 26°

Weather

18 mm
Rainfall
3.1 m/s
Wind
Light Breeze

October

October is cool with highs of 22°C and lows of 11°C. Light rainfall.

Comfort

17°
Feels Like Cool
17°C
Temperature
11° 22°

Weather

19 mm
Rainfall
3.1 m/s
Wind
Light Breeze

November

November is cool with highs of 17°C and lows of 6°C. Regular rainfall (96 mm).

Comfort

11°
Feels Like Cool
11°C
Temperature
17°

Weather

96 mm
Rainfall
3.4 m/s
Wind
Light Breeze

December

December is cold with highs of 13°C and lows of 4°C. Significant rainfall (108 mm).

Comfort

Feels Like Cold
C
Temperature
13°

Weather

108 mm
Rainfall
3.6 m/s
Wind
Light Breeze

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