During which seasonal period are San Francisco garter snakes most visible for active basking and hunting?

Late spring through early autumn

The visibility of the San Francisco garter snake is strongly linked to ambient temperatures, as they are ectotherms relying on external sources to regulate their body temperature, a process known as basking. While they retreat deep into burrows or under cover during the cooler, wetter winter months to escape the cold, their period of peak activity occurs when temperatures are consistently warmer. This active phase, during which they bask to raise their internal temperature for digestion and hunting, typically spans from late spring and continues throughout the early autumn period. During these warmer, drier months, they are more frequently found along the edges of aquatic habitats or in basking spots adjacent to their terrestrial cover.