Sammamish, Washington planting calendar and frost dates
Sammamish is in USDA hardiness zone 8b. The last spring frost typically comes around March 8 and the first fall frost around November 23, giving about 259 frost-free days a year.
- Hardiness zone
- Zone 8b
- Typical last frost
- March 8
- Typical first frost
- November 23
- Frost-free season
- 259 days
Frost dates in Sammamish
Last spring frost
- February 13Risky: frost later than this in 9 years out of 10
- March 8Typical: a later frost in half of years
- March 29Safe: a later frost only 1 year in 10
First fall frost
- November 4Risky: frost earlier than this 1 year in 10
- November 23Typical: an earlier frost in half of years
- December 16Late: frost before this in 9 years out of 10
The growing season between the typical last and first frosts is about 259 days. Frost here means a low of 32°F at the weather station. A hard freeze (28°F), which damages most hardy crops too, typically ends around February 11 and returns around December 11.
NOAA U.S. Climate Normals 1991-2020 for Seattle Sand Pt Wsfo, 12.3 miles NW of the city center and 347 feet lower. Low-lying and rural spots often frost later in spring and earlier in fall than airports and city centers.
What to plant each month in Sammamish
January
Start indoors: black-eyed susans, broccoli, cabbages, cauliflower, chives, cilantro, collard greens, kale, leeks, lettuce, marigolds, nasturtiums, oregano, parsley, petunias, ranunculus, rosemary, sage, snapdragons, spinach, swiss chard
Plant or sow outdoors: black-eyed susans, blueberries, garlic, grapes, grass seed, hollyhocks, onions, peas, poppies, raspberries, rhubarb, strawberries, turnips, wildflowers
February
Start indoors: cilantro, marigolds, nasturtiums, ranunculus, spinach, swiss chard, zinnias
Plant or sow outdoors: beets, black-eyed susans, blackberries, blueberries, broccoli, cabbages, carrots, cauliflower, chives, cilantro, collard greens, dahlias, dill, figs, garlic, gladioli, grapes, grass seed, hollyhocks, kale, leeks, lettuce, onions, parsley, peas, poppies, radishes, ranunculus, raspberries, rhubarb, roses, snapdragons, spinach, strawberries, swiss chard, turnips, wildflowers
March
Start indoors: ginger, peppers
Plant or sow outdoors: beets, carrots, cauliflower, chives, cilantro, dahlias, dill, figs, garden mums, gladioli, grapes, lavenders, leeks, lettuce, lilies, marigolds, mints, nasturtiums, oregano, parsley, petunias, ranunculus, rosemary, roses, sage, snapdragons, spinach, swiss chard, thyme, zinnias
April
Start indoors: basil, celery, eggplants, peppers, tomatoes
Plant or sow outdoors: asparagus, garden mums, green onions, potatoes, st. augustinegrass, sunflowers, sweet corn
May
Start indoors: basil, cantaloupes, cosmos, cucumbers, okra, pumpkins, watermelons, winter squash, zucchini
Plant or sow outdoors: asparagus, ginger, green onions, kentucky bluegrass, st. augustinegrass, sunflowers, sweet peas, tall fescue
June
Plant or sow outdoors: basil, cantaloupes, cucumbers, eggplants, green beans, green onions, peppers, pumpkins, tomatoes, watermelons, winter squash, zucchini
July
Plant or sow outdoors: bermudagrass, celery, centipedegrass, cosmos, okra, peanuts, sweet potatoes, zoysiagrass
August
Plant or sow outdoors: bermudagrass, centipedegrass, zoysiagrass
Plant for fall: bearded irises, brussels sprouts, carrots, collard greens, lettuce, peas, potatoes, snapdragons, sweet corn, swiss chard
September
Plant for fall: azaleas, bearded irises, beets, broccoli, cabbages, carrots, cauliflower, clematis, collard greens, coneflowers, daylilies, hostas, hydrangeas, kale, lettuce, peas, radishes, roses, saffron, snapdragons, spinach, swiss chard, turnips
October
Plant for fall: azaleas, bearded irises, beets, broccoli, cabbages, cauliflower, clematis, coneflowers, crocuses, daffodils, daylilies, grass seed, hostas, hyacinths, hydrangeas, kale, lilies, ornamental alliums, peonies, radishes, roses, saffron, spinach, tulips, turnips
November
Start indoors: onions
Plant for fall: crocuses, daffodils, daylilies, garlic, hyacinths, lilies, ornamental alliums, peonies, tulips
December
Start indoors: broccoli, cabbages, cauliflower, collard greens, kale, leeks, onions, oregano, parsley, petunias, ranunculus, rosemary, snapdragons
Plant for fall: crocuses, garlic, hyacinths, ornamental alliums, tulips
Frost dates and zones by ZIP code in Sammamish
Sammamish's 3 main ZIP codes take their frost dates from 2 different NOAA stations: the typical last frost ranges from March 8 in 98074 to March 30 in 98029. Every one of them is in zone 8b.
| ZIP code | Zone | Weather station | Typical last frost | Typical first frost |
|---|---|---|---|---|
| 98029 | 8b | Snoqualmie Falls, 8.3 mi E | Mar 30 | Nov 7 |
| 98074 | 8b | Seattle Sand Pt Wsfo, 10.8 mi WNW | Mar 8 | Nov 23 |
| 98075 | 8b | Seattle Sand Pt Wsfo, 12.3 mi NW | Mar 8 | Nov 23 |
Seattle Sand Pt Wsfo also supplies the frost dates for Seattle, Bellevue, Kirkland, Redmond, Shoreline and Bothell, so their planting calendars match Sammamish's.
Planting dates for popular crops in Sammamish
| Plant | Start indoors | Plant or sow outdoors | Fall planting |
|---|---|---|---|
| Tomatoes | Apr 11 to 25 | Jun 6 to 20 | — |
| Strawberries | — | Jan 25 to Feb 8 | — |
| Lettuce | Jan 11 to 25 | Mar 1 to 15 | Aug 24 to Sep 28 |
| Cilantro | Jan 25 to Feb 8 | Mar 8 to 15 | — |
| Basil | Apr 18 to May 2 | Jun 6 to 13 | — |
| Potatoes | — | Apr 12 to 19 | Aug 3 to 10 |
| Garlic | — | Jan 25 to Feb 8 | Nov 23 to Dec 7 |
| Onions | Nov 16 to Dec 28 | Feb 8 to 22 | — |
| Cucumbers | May 9 to 23 | Jun 6 to 20 | — |
| Pumpkins | May 9 to 23 | Jun 6 to 20 | — |
| Peppers | Mar 21 to Apr 18 | Jun 6 to 20 | — |
| Carrots | — | Feb 15 to Mar 8 | Aug 31 to Sep 21 |
| Sweet Potatoes | — | Jul 6 to 13 | — |
| Watermelons | May 2 to 16 | Jun 6 to 20 | — |
| Sweet Corn | — | Apr 12 to 26 | Aug 17 to 31 |
| Green Beans | — | Jun 6 to 20 | — |
| Zucchini | May 9 to 23 | Jun 6 to 20 | — |
| Broccoli | Dec 21 to Jan 11 | Feb 8 to 22 | Sep 7 to Oct 5 |
| Peas | — | Jan 25 to Feb 8 | Aug 31 to Sep 14 |
| Spinach | Jan 25 to Feb 1 | Mar 1 to 15 | Sep 14 to Oct 19 |
| Sunflowers | — | Apr 12 to May 3 | — |
| Zinnias | Feb 8 to 15 | Mar 8 to 22 | — |
| Tulips | — | — | Oct 12 to Dec 7 |
| Daffodils | — | — | Oct 12 to Nov 23 |
| Grass Seed | — | Jan 25 to Feb 8 | Oct 12 to 26 |
Nearby cities
- Bellevue, WA zone 8b, last frost Mar 8
- Redmond, WA zone 8b, last frost Mar 8
- Kirkland, WA zone 9a, last frost Mar 8
- Renton, WA zone 9a, last frost Mar 20
- Bothell, WA zone 8b, last frost Mar 8
- Seattle, WA zone 9a, last frost Mar 8
Planting in WashingtonAbout zone 8bPrintable calendar for Sammamish
Questions
When is the last frost in Sammamish?
Around March 8 in a typical year, based on NOAA's 1991-2020 records for Seattle Sand Pt Wsfo. There is still a 1 in 10 chance of frost after March 29.
What planting zone is Sammamish in?
USDA hardiness zone 8b (2023 map). The zone tells you which perennials survive the winter; planting dates depend on frost dates instead.
When should I plant tomatoes in Sammamish?
Start seeds indoors April 11 to 25 and set plants out June 6 to 20.
When is the first frost in Sammamish?
Around November 23 in a typical year, and before November 4 about 1 year in 10.