Mt. Wilson Bike Climb - PJAMM Cycling

18.5 mi
4,600 ft
4.5 %



Climb by bike to Mt. Wilson Observatory - one of the longer and more challenging bicycle climbs in Southern California.  
The grade on this climb fluctuates frequently with multiple transitions from low gradients of 2-4% up to 7-10% grades.  However, only a fraction (2.7%) of this climb reaches double digits.  The steepest quarter mile is 9% towards the end of the climb and the steepest mile is only 6.4%.  There is a 1.6 mile -2% descent beginning at mile 8.3.  Eliminating the descent on this climb raises the grade from 4.5% to 5.4%.
Roadway:  The road was in excellent condition as of 2018.

Traffic:  Traffic over the first several miles on Highway 2 can be moderate and fast moving, but there is a ~3-foot shoulder consistently, and frequent pullouts. However, after few miles the traffic on Highway 2 lessens to mild.  There is minimal traffic on Mt. Wilson Road for the last 4.2 miles of the climb. 

Parking:  We parked on a parallel side street at the start of the climb for our 2 trips up Mt. Wilson.  MapStreet View
Provisions:  There are no spots for food or water on this climb until the Cosmic Cafe at Mt. Wilson.  However, as of December 2020 the Cafe had been closed due to COVID.  Check the Cosmic Cafe at Mt. Wilson Observatory Facebook Page for details before your climb if you are interested in a meal there at the end of your climb. 

Gear:  As with all climbs to much higher altitude than your starting location (here 4,000' change) be sure to check the PJAMM Weather Tool for weather conditions at the finish around the time you intend to arrive and pack accordingly.  
Before heading out on any cycling adventure check out our Things to Bring on a Cycling Trip and use our interactive check list to ensure you don't forget anything.
Consider visiting the Mt. Wilson Observatory at the finish of the climb - see Full Summary for more details (Google Map + Reviews). 

Mt. Wilson is not far from some of the great Santa Monica Mountains bike climb (Santa Monica Mountains).  It is only 15 miles from one of our favorite Southern California bike climbs - Hollywood Sign Bike Ride



Difficulty: Challenging



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Aug 14, 2021
difficulty: Challenging
scenery: 4
traffic: 2
road: 4
Aug 14, 2021
scenery: 4
traffic: 2
road: 4
Ugly traffic, even early on a Saturday in July (2021) - car clubs and motorcycles ripping it up the road, and not much of a shoulder to cycle on. There is a water stop at Red Box Trailhead, which is where things turn absolutely beautiful.
Jun 19, 2021
difficulty: Challenging
scenery: 3
traffic: 3
road: 5
Jun 19, 2021
scenery: 3
traffic: 3
road: 5
If you don’t like traffic/ motorcycles/ race cars go early! I started at 7AM on Saturday and the traffic was definitely manageable on Highway 2. The descent later in the day was much less enjoyable however. Even though you are going just as fast as the cars they still seem to want to get around you. The first two miles are the steepest and then the climb is super consistent at about 5% except for one minor flat section around mile 9 and two small downhills in the last 4 miles. Highly recommend this climb, just make sure you bring enough water as there is nowhere to get water except maybe the cafe at the top of the observatory but it doesn’t open until 10AM.

Climb Profile Not Found

Cycling Mt. Wilson -- a top Southern California bike climb beginning in La Cańada Flintridge

Ride 18.1 miles gaining 5,376’ to elevation 5,658 at 4.5% average grade.

Beginning in Flintridge, we ride through a residential area for 1.8 miles to the point where road narrows to two lanes and becomes more rural and scenic.  While this is a great climb from mile 9.2 on[1], the first nine miles are unpleasant due to a narrow shoulder and heavy traffic that travels at highway speeds (60mph+).  At the junction of Highway 2 and County Route N3, we continue on Highway 2 for another 4.5 miles to Mt Wilson Road.  The grade on this route is fairly steady, in the 4-6% range and rarely exceeding 7%.

Road sign at beginning of Mt. Wilson climb by bike     

Start of ride.

 Roadway sign on Hwy 2 during bike climb

First 13.8 miles of this bicycle climb are on Highway 2.

The most scenic and less nerve-wracking (i.e., lighter traffic) part of this climb is from mile 9 to the radio towers at the top at mile 18.  We turn off of Highway 2 at mile 13.8 and it is approximately four miles to the television towers at the top of the climb.

Angeles National Forest road sign on Hwy 2 during bicycle ride to Mt. Wilson

Enter Angeles National Forest at mile 2.3,

Established 1908 by Teddy Roosevelt; 655,387 acres.


Turn onto Mt. Wilson-Red Box Road at mile 13.7

4.3 miles at 4.6% to TV Towers and end of bike climb.

The road from Highway 2 to the top is very scenic and along a portion of the road that has sheer drop-offs just over a short rock barrier.  There are excellent views of San Gabriel Peak to the southeast for the first mile, we pass through Eaton Saddle at mile 16.2, and for the next couple of miles have great views of Highway 2 and the San Gabriel Mountains to the northeast as we continue up Mt. Wilson road.   



Mt. Wilson Red Box Road -- Wilson Observatory in photo middle.

This climb ends at the KCAL TV towers at mile 18.  The Mt. Wilson Observatory is another half mile past our end point, but at a lower elevation.

Just about to the top.

Excellent views of Los Angeles from the top of this climb.

Before heading out to climb Mt. Wilson, be sure to rely on our list of Things to Bring on a Cycling Trip, and use our interactive checklist to ensure you don't forget anything.


The Mount Wilson observatory was founded in 1904 by solar astronomer George Ellory Hale and his team.  Hale acted as director of the observatory until his retirement in 1923.  An informative article about Hale’s life and the beginnings of the Mount Wilson observatory can be found here.  Hale had an accomplished scientific life, and is best known for his discovery of magnetic fields in sunspots, and in addition to founding Mount Wilson, he also founded the Yerkes Observatory, Palomar Observatory, and the Hale Solar Laboratory.  More information on Hale can also be found here.

We arrived too early to visit the observatory.

Hours as of August 2019 were 10 a.m. to 5 p.m.

Einstein visits the observatory in 1931.

Evidence supporting the theory of relativity was gathered here.


Inside the observatory


Today, the observatory is open for free tours from 10 a.m. to 5 p.m. and is home to two historical telescopes:  The 100” Hooker telescope which was the largest aperture telescope in the world from 1917 to 1949, and the original 60” telescope which was the largest in the world when it was completed in 1908. The first telescope on Mt. Wilson was built in 1904 and funded by the Carnegie Institution of Washington.

Due to the inversion layer that traps smog over Los Angeles, at 5,710’, Mount Wilson has the steadiest air in North America.  Thank you LA smog...I guess???

Inversion layer at work.

The brown line just below the blue in the center of the photo is smog.

This is the alternate route to Dawson Saddle (Map) which avoids the six miles of closed Highway 39 along the “main” Dawson Saddle climb, but is also much longer (45 miles to the Saddle, making it just over twice the length of the more traditional route) and includes a little over 2,000’ of descent -- so, it is not a true Top Climb, by Fiets standards, anyway.  We also must travel along the busy section of Highway 2 for 10 miles.

Roadway Surface and Traffic Report:  Highway 2 has a very narrow bike lane which is often merely a white line with 6” of pavement and loose gravel to the right.  Traffic is heavy and fast-moving for the first 9 miles of the climb.  For those who wish to avoid highway traffic, do not undertake this climb, or begin at mile 9.2, after the junction of Highway 2 and County Route 3.

That’s a wrap!

[1] Most of the traffic along the first stretch of Highway 2 turns onto Angeles Forest Highway (County Route N3) at the 9.2 mile mark, this is the route to Palmdale and a connector to Highway 14.