Thermalito Afterbay is a reservoir-based kitesurfing location in the Sacramento Valley of northern California. The spot features an east-facing shoreline with multiple peninsulas and coves along the southern access area shown in the satellite image. The water body is a managed irrigation reservoir with relatively consistent water levels but limited wind exposure due to its inland location and surrounding terrain.
This spot is characterized by low average wind speeds (5.4 knots) and very poor wind reliability (2.6%), making it challenging for consistent kitesurfing sessions. The lake offers protected coves suitable for beginners when wind is present, but conditions are highly variable. The presence of numerous shallow areas, submerged rocks, and recreational boat traffic creates navigational hazards. Side-shore winds from the south are ideal when available. The narrow channels between peninsulas restrict riding area and can create turbulent wind patterns. This location is best suited for beginners seeking flat-water practice during rare favorable wind days, though the unreliable conditions make it unsuitable for serious progression or regular sessions.