This climb ranks #8 on the Tri-County Top Climb list with Fiets Index of 4.0. The first couple miles of the climb are generally shaded under a canopy of trees. Just past 2 miles, we encounter a very sharp left turn and the road pitches up dramatically for most of the remaining second half of the climb - 1.9 miles, 1,100' at 11.2% average grade. This is a beautiful climb - the first several miles are rural and wooded, while the steeper last half treats us to classic Napa County hillside vineyards, quite spectacular in the spring and summer - truly some of the best vineyard-climb views in Napa County.
This climb can be broken into 2 separate ascents, Spring Mountain #1 (2.2 miles / 532' / 4.2% average grade) and Spring Mountain #2 (1.9 miles / 1,100 / 11.2% average grade).
Traffic/Roadway surface: The road is wide with a bike lane much of the way and the surface is excellent. Traffic is mild to moderate.