B2 Major Climate Type Definitions
Use the following information along with Table B-4 to determine climate zone numbers and letters for international climate zones.
Marine (C) definition—Locations meeting all four criteria:
- Mean temperature of coldest month between 27°F and 65°F.
- Warmest month mean <72°F.
- At least four months with mean temperatures over 50°F.
- Dry season in summer. The month with the heaviest precipitation in the cold season has at least three times as much precipitation as the month with the least precipitation in the rest of the year. The cold season is October through March in the Northern Hemisphere and April through September in the Southern Hemisphere.
Dry (B) definition—Locations meeting the following criteria: not marine and
Pin < 0.44 × (TF — 19.5)
|P||=||annual precipitation, in.|
|T||=||annual mean temperature, °F|
Moist (A) definition—Locations that are not marine and not dry.