Palomar Mountain stands apart from the ranges around it, an isolated forested massif that rises above the dry hills of northern San Diego County, and the East Grade Road is the best way to reach it on two wheels. It leaves the valley near Lake Henshaw and climbs through a series of tight hairpins, gaining about a thousand metres in a short distance. The road is narrow, with steep drops, blind corners and patchy surfaces, and it asks for concentration and a low speed. Large vehicles are discouraged, which suits riders.
At the top, the air changes. The mountain is covered in pines, firs and oaks, with meadows and campgrounds, and the temperature can be ten degrees cooler than in the valley. The summit is home to the Palomar Observatory, built in the 1930s and completed in 1948, with the 200-inch Hale telescope, which was the largest in the world for decades. It is operated by the California Institute of Technology, and visitors can walk into the gallery of the dome during opening hours, which are limited, so check ahead. The big white dome among the trees is a surprising sight, and the quiet inside is almost reverent.
Riding the East Grade is a highlight of the region. The curves are tight and rhythmic, the views open suddenly over the valley and the lake far below, and the climb through different vegetation zones is a lesson in how quickly the climate changes. The surface can be rough, with potholes, loose gravel and sometimes oil, and the road gets damp and cold in shade. Winter brings snow and ice, and the road may be closed or require chains, so check conditions between November and March. In summer, the heat in the valley is fierce, and the mountain is a relief.
A small store and a few campgrounds operate in season, but do not count on them. Valley Center, about nineteen kilometres away, and Ramona have fuel and food, so fill up before you go. Bring water, because you will want it on the climb.
Wildlife includes deer, wild turkeys and squirrels, and on the descent you may meet cyclists climbing the grade, so give them space. Go on a weekday if you can, and take your time on every corner.