Posted on 2nd May 2013 @ 7:03 PM
Growing season: early June through Aug., but with some variation--the longest seasons are usually found near this zone's large bodies of water. Frost can come any night of the year. Winters are snowy and intensely cold, due to latitude, elevation, and/or influence of continental air mass. There's some summer rainfall.
Growing season: early May through Sept. Winters are cold (lows run from -3 degrees to -34 degrees F/-19 degrees to -37 degrees C), but less so than in Zone 1. In northern and interior areas, lower elevations fall into Zone 2, higher areas into Zone 1.
Growing season: early May to late Sept.--shorter than in Zone 2, but offset by milder winters (lows from 13 degrees to -24 degrees F/-11 degrees to -31 degrees C). This is fine territory for plants needing winter chill and dry, hot summers.
Growing season: early May to early Oct. Summers are cool, thanks to ocean influence; chilly winters (19 degrees to -7 degrees F/-7 degrees to -22 degrees C) result from elevation, influence of continental air mass, or both. Coolness, ample rain suit many perennials and bulbs.
Growing season: mid-April to Nov., typically with cool temperatures throughout. Less rain falls here than in Zone 4; winter lows range from 28 degrees to 1 degree F/-2 degrees to -17 degrees C. This "English garden" climate is ideal for rhododendrons and many rock garden plants.
Growing season: mid-Mar. to mid-Nov., with somewhat warmer temperatures than in Zone 5. Ocean influence keeps winter lows about the same as in Zone 5. Climate suits all but tender plants and those needing hot or dry summers.
Growing season: May to early Oct. Summers are hot and dry; typical winter lows run from 23 degrees to 9 degrees F/-5 degrees to -13 degrees C. The summer-winter contrast suits plants that need dry, hot summers and moist, only moderately cold winters.
Growing season: mid-Feb. through Nov. This is a valley floor with no maritime influence. Summers are hot; winter lows range from 29 degrees to 13 degrees F/-2 degrees to -11 degrees C. Rain comes in the cooler months, covering just the early part of the growing season.
Growing season: late Feb. through Dec. Zone 9 is located in the higher elevations around Zone 8, but its summers are just as hot; its winter lows are slightly higher (temperatures range from 28 degrees to 18 degrees F/-2 degrees to -8 degrees C). Rainfall pattern is the same as in Zone 8.
Growing season: April to early Nov. Chilly (even snow-dusted) weather rules from late Nov. through Feb., with lows from 31 degrees to 24 degrees F/-1 degree to -4 degrees C. Rain comes in summer as well as in the cooler seasons.
Growing season: early April to late Oct. Summers are sizzling, with 110 days above 90 degrees F/32 degrees C. Balancing this is a 3 1/2-month winter, with 85 nights below freezing and lows from 11 degrees to 0 degrees F/-12 degrees to -18 degrees C. Scant rainfall comes in winter.
Growing season: mid-Mar. to late Nov., with scorching midsummer heat. Compared to Zone 13, this region has harder frosts; record low is 6 degrees F/-14 degrees C. Rains come in summer and winter.
Growing season: mid-Feb. through Nov., interrupted by nearly 3 months of incandescent, growth-stopping summer heat. Most frosts are light (record lows run from 19 degrees to 13 degrees F/-17 degrees to -11 degrees C); scant rain comes in summer and winter.
Growing season: early Mar. to mid-Nov., with rain coming in the remaining months. Periodic intrusions of marine air temper summer heat and winter cold (lows run from 26 degrees to 16 degrees F/-3 degrees to -9 degrees C). Mediterranean-climate plants are at home here.
Growing season: Mar. to Dec. Rain comes from fall through winter. Typical winter lows range from 28 degrees to 21 degrees F/-2 degrees to -6 degrees C. Maritime air influences the zone much of the time, giving it cooler, moister summers than Zone 14.
Growing season: late Feb. to late Nov. With cold air draining to lower elevations, winter lows typically run from 32 degrees to 19 degrees F/0 degrees to -7 degrees C. Like Zone 15, this region is dominated by maritime air, but its winters are milder on average.
Growing season: late Feb. to early Dec. Coolness and fog are hallmarks; summer highs seldom top 75 degrees F/24 degrees C, while winter lows run from 36 degrees to 23 degrees F/2 degrees to -5 degrees C. Heat-loving plants disappoint or dwindle here.
Growing season: mid-Mar. through late Nov. Summers are hot and dry; rain comes in winter, when lows reach 28 degrees to 10 degrees F/-2 degrees to -12 degrees C. Plants from the Mediterranean and Near Eastern regions thrive here.
Growing season: early Mar. through Nov. As in Zone 18, rainy winters and hot, dry summers are the norm--but here, winter lows dip only to 27 degrees to 22 degrees F/-3 degrees to -6 degrees C, allowing some tender evergreen plants to grow outdoors with protection.
Growing season: late Mar. to late Nov.--but fairly mild winters (lows of 28 degrees to 23 degrees F/-2 degrees to -5 degrees C) allow gardening through much of the year. Cool and moist maritime influence alternates with hot, dry interior air.
Growing season: early Mar. to early Dec., with the same tradeoff of oceanic and interior influence as in Zone 20. During the winter rainy season, lows range from 36 degrees to 23 degrees F/2 degrees to -5 degrees C--warmer than in Zone 20, since the colder air drains to the valleys.
Growing season: Mar. to early Dec. Winter lows seldom fall below 28 degrees F/-2 degrees C (records are around 21 degrees F/-6 degrees C), though colder air sinks to this zone from Zone 23. Summers are warm; rain comes in winter. Climate here is largely oceanic.
Growing season: almost year-round (all but first half of Jan.). Rain comes in winter. Reliable ocean influence keeps summers mild (except when hot Santa Ana winds come from inland), frosts negligible; 23 degrees F/-5 degrees C is the record low.
Growing season: all year, but periodic freezes have dramatic effects (record lows are 33 degrees to 20 degrees F/1 degree to -7 degrees C). Climate here is oceanic (but warmer than oceanic Zone 17), with cool summers, mild winters. Subtropical plants thrive.
Growing season: all year. Add ample year-round rainfall (least in Dec. through Mar.), high humidity, and overall warmth, and you have a near-tropical climate. The Keys are frost-free; winter lows elsewhere run from 40 degrees to 25 degrees F/4 degrees to -4 degrees C.
Growing season: early Feb. to late Dec., with typically humid, warm to hot weather. Rain is plentiful all year, heaviest in summer and early fall. Lows range from 15 degrees F/-9 degrees C in the north to 27 degrees F/-3 degrees C in the south; arctic air brings periodic hard freezes.
Growing season: early Mar. to mid-Dec.. Summers are hot and humid; winter lows only rarely dip below freezing. Many plants from tropical and subtropical Africa and South America are well adapted here.
Growing season: mid-Mar. to early Dec. Humidity and rainfall are year-round phenomena; summers are hot, winters virtually frostless but subject to periodic invasions by frigid arctic air. Azaleas, camellias, many subtropicals flourish.
Growing season: mid-Mar. through Nov. Moderate rainfall (to 25" annually) comes year-round. Summers are hot. Winter lows can dip to 26 degrees F/-3 degrees C, with occasional arctic freezes bringing much lower readings.
Growing season: mid-Mar. through Nov. Zone 30 has higher annual rainfall than Zone 29 (to 35") and lower winter temperatures, normally to around 20 degrees F/-7 degrees C. Seasonal variations favor many fruit crops, perennials.
Growing season: mid-Mar. to early Nov. In this extensive east-west zone, hot and sticky summers contrast with chilly winters (record low temperatures are 7 degrees to 0 degrees F/-14 degrees to -18 degrees C). There's rain all year (an annual average of 50"), with the least falling in Oct.
Growing season: late Mar. to early Nov. Rain falls year-round (40" to 50" annually); winter lows (moving through the zone from south to north) are 30 degrees to 20 degrees F/-1 degree to -7 degrees C. Humidity is less oppressive here than in Zone 31.
Growing season: mid-April through Oct. Warm Gulf Coast air and colder continental/arctic fronts both play a role; their unpredictable interplay results in a wide range in annual rainfall (22" to 52") and winter lows (20 degrees to 0 degrees F/-7 degrees to -18 degrees C). Summers are muggy and warm to hot.
Growing season: late April to late Oct. Ample rainfall and humid summers are the norm. Winters are variable--typically fairly mild (around 20 degrees F/-7 degrees C), but with lows down to -3 degrees to -22 degrees F/-19 degrees to -30 degrees C if arctic air swoops in.
Growing season: late April to late Oct. Rain comes in all seasons. Summers can be truly hot and humid. Without arctic fronts, winter lows are around 18 degrees F/-8 degrees C; with them, the coldest weather may bring lows of -20 degrees F/-29 degrees C.
Growing season: May to late Oct. Thanks to greater elevation, summers are cooler and less humid, winters colder (0 degrees to -20 degrees F/-18 degrees to -29 degrees C) than in adjacent, lower zones. Rain comes all year (heaviest in spring). Late frosts are common.
Growing season: May to mid-Oct., with rainfall throughout. Lower in elevation than neighboring Zone 42, with warmer winters: lows are 0 degrees to -5 degrees F/-18 degrees to -21 degrees C, unless arctic air moves in. Summer is warm to hot, humid.
Growing season: May to early Oct. Summers feature reliable rainfall and lack oppressive humidity of lower-elevation, more southerly areas. Winter lows dip to -10 degrees to -20 degrees F/-23 degrees to -29 degrees C , with periodic colder temperatures due to influxes of arctic air.
Growing season: early May to early Oct. Springs and summers are cooler here, autumns milder than in areas farther from the lakes. Southeast lakeshores get the heaviest snowfalls. Lows reach 0 degrees to -10 degrees F/-18 degrees to -23 degrees C.
Growing season: mid-May to mid-Sept., with rainy, warm, variably humid weather. The lakes help moderate winter lows; temperatures typically range from -10 degrees to -20 degrees F/-23 degrees to -29 degrees C, with occasional colder readings when arctic fronts rush through.
Growing season: early May to early Oct. Winter brings average lows of -11 degrees to -20 degrees F/-23 degrees to -29 degrees C. Summers in this zone are hotter and longer west of the Mississippi, cooler and shorter nearer the Great Lakes; summer rainfall increases in the same west-to-east direction.
Growing season: late May to late Sept. This zone's elevation gives it colder winters than surrounding zones: lows range from -20 degrees to -40 degrees F/-29 degrees to -40 degrees C, with the colder readings coming in zone's Canadian portion. Summers are humid, rainy.
Growing season: late May to mid-Sept. The climate is humid from spring through early fall; summer rains are usually dependable. Arctic air dominates in winter, with lows typically from -20 degrees to -30 degrees F/-29 degrees to -34 degrees C.
Growing season: June to mid-Sept. Latitude and elevation give fairly cool, rainy summers, cold winters with lows of -20 degrees to -40 degrees F/-29 degrees to -40 degrees C. Choose short-season, low heat-requirement annuals and vegetables.
Growing season: mid-June through Aug., with rain throughout; rainfall (and humidity) are least in zone's western part, greatest in eastern reaches. Winters are frigid (-30 degrees to -40 degrees F/-34 degrees to -40 degrees C), with snow cover, deeply frozen soil.