Sunset ZONE 14: Orleans, Weitchpec, Hoopa, Willow Creek.  Northern California's inland areas with some ocean influence

The marine air that spills inland via the Klamath and Trinity canyons moderates has a strong influence on this climate zone, delineating it's boundaries. Summer temperatures climb regularly into the triple digits in this area, producing some of the earliest tomatoes and peaches at the coastal farmers markets. The valley floors in this area are subject to hard winter frosts. There can be a 50 degree temperature swing between daytime highs and nighttime lows, a phenomenon that builds complex flavors an character in tree fruit and wine grapes. Crops that require lots of heat (i.e. peaches, tomatoes, peppers, eggplants, figs,) or lots or cold (i.e. fruit trees that require winter chill) do well here. Fruit trees and berries that do not do well with extreme heat, such as apples, filberts, blueberries, benefit from being planted where afternoon shade provides relief from the most intense heat. A long growing season means year round gardening. Clear, dry spells in the winter can lead to a pattern of hard frosts that can be hard on winter gardens. Over a 20-year period, this area had lows ranging from 26 to 16º F (–3 to –9ºC). Weather records show all-time lows from 20 down to 11ºF (–7 to –12º C).

ZONE 15: Inland Slopes of the Coast Range and Siskiyous, from Willow Creek to Orleans, with Marine Influence.  

Head west from route 96 on a hot summer day on any of the roads that climb steeply from the Klamath River Canyon and you're liable to encounter coastal fog that spills over the mountains and gives rise to a dense forest that includes coastal species such as rhododendron, azalea, salal and Port Orford Cedar. The slope and coastal influence tempers the extremes of summer heat and winter chill found at the valley floors for the Klamath and Trinity. Zones 15 and 16 are areas of Central and Northern California that are influenced by marine air approximately 85 percent of the time and by inland air 15 percent of the time. The cold-winter areas that make up Zone 15 lie in cold-air basins, on hilltops above the thermal belts, or far enough north that plant performance dictates a Zone 15 designation. Many plants that are recommended for Zone 15 are not suggested for Zone 14 mainly because they must have a moister atmosphere, cooler summers, milder winters, or all three conditions present at the same time. On the other hand, Zone 15 still receives enough winter chilling to favor some of the coldwinter specialties, such as English bluebells, which are not recommended for Zones 16 and 17. Lows over a 20-year period ranged from 28 to 21°F (–2 to –6°C), and record lows from 26 to 16°F (–3 to –9°C).

Sunset ZONE 7: North of Somes Bar, Salmon River Lower Elevations, Happy Camp, Seiad Valley,  inland areas with diminishing coastal influence; California’s Gray Pine Belt.  

The "river fog" that creeps up the Klamath from the coast typically makes it no farther than Somes Bar, marking the transition between zone 14 and Zone 7. Zone 7 is named for the Gray pines that rim the mid elevation around the Central Valley, in our region mingled with more adaptable incense cedars. Average temperatures are lower than zone 14, the occasional snow that reaches the lower elevations of the Mid Klamath are likely to stick around a bit longer here. Microclimates can make a big difference for gardening - south and west aspects with some elevation are markedly warmer and enjoy more frost free days. This is an ideal climate for plants that require a marked seasonal pattern—flower bulbs, peonies, lilacs, and flowering cherries, for example. Deciduous fruit trees (apples, pears, apples, peaches, and cherries) do well. At weather-recording stations in Zone 7, typical winter lows range from 35 to 26°F (2 to –3°C),with record lows averaging from 18 to -0° F (–8 to –18°C)

ZONE 1A: Coldest high elevation areas of the Mid Klamath

Climb high enough in the Mid Klamath and eventually you hit the coldest climate zone where extended low winter temperatures are the most limiting factor, shortening the growing season and ruling out any plants that are not frost hardy. Marked by a short growing season and relatively mild summer temperatures, Zone 1A includes the coldest regions west of the Rockies, excluding Alaska, and a few patches of cold country east of the Great Divide. The mild days and chilly nights during the growing season extend the bloom of summer perennials like columbines and Shasta daisies. If your garden gets reliable snow cover (which insulates plants), you’ll be able to grow perennials listed for some of the milder zones. In years when snow comes late or leaves early, protect plants with a 5- or 6-inch layer of organic mulch. Along with hardy evergreen conifers, tough deciduous trees and shrubs form the garden’s backbone. Gardeners can plant warm-season vegetables as long as they are short-season varieties. To further assure success, grow vegetables from seedlings you start yourself or buy from a nursery or garden center. Winter lows average in the 0 to 11°F (–18 to –12°C) range; extremes range from –25 to –50°F (–32 to –46°C). The growing season is 50 to 100 days.

ZONE 4: Mid to High Elevations of the Mid Klamath, areas with Cold Winters

As one gains elevation in the Mid Klamath the growing season shortens due to late Spring and early Fall frost, and more snow in the winter.  One of the West’s most narrow, linear climates, Zone 4 runs from high in the coastal mountains of Northern California to southeastern Alaska, losing elevation as it moves north. It gets considerable influence from the Pacific Ocean, but also from higher elevation. Extending the season with a cold frame, greenhouse and row covers is key to a productive garden.  

Average winter lows in Zone 4 range from 34°F (1°C) down to 28°F (–2°C),with extreme lows averaging 8 to 0°F (–13 to –18°C). The growing season is 150 to 200 days long, but because Zone 4 summers are temperate (highs average from the low 60s to the 70s), plants take more time to develop. If you’re growing vegetables, for example, add at least 50 percent to the days-to-harvest figure listed on the seed package, or start your garden from transplants.

USDA Climate Zones of the Klamath-Trinity

Most gardeners are familiar with the USDA zones listed in the adjacent map and chart, they account only for the minimum average annual temperature so they are used to rate a plant’s cold-hardiness.  Using this system, most of the Mid Klamath falls into climate zones 8 & 9.