Csb

Csb is a subtype of the temperate (mesothermal) climate in the Köppen climate classification. It denotes a temperate climate with dry summers and warm summers. In climate data terms, the coldest month typically averages above −3°C and below 18°C, and the warmest month averages below 22°C. The defining feature is a dry summer; the summer months receive notably less precipitation than the wettest winter months, with at least one summer month receiving relatively little rainfall (commonly under 30–40 mm). The warmest-month threshold used to distinguish this subtype is the “b” designation, indicating the warmest month is not hot and that four or more months exceed 10°C.

The Csb pattern features mild, wet winters and relatively dry summers, with maritime or elevated influences moderating temperatures. Precipitation tends to be concentrated in autumn and winter, while summers are drier and sun-exposed, though not typically hot. Regions with Csb climates include coastal areas of western Europe and parts of the Pacific Northwest in North America.

In practice, Csb supports agricultural crops that tolerate dry summers and cool to warm growing seasons, such as certain grape varieties and other fruits adapted to Mediterranean-like but cooler summers. It is one of several subtypes in the Köppen system used to describe global climate, and it contrasts with Csa (hot-summer Mediterranean) and Cfb (oceanic).