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Frost dates and planting calendar for Grants Pass, Oregon

Updated October 30, 2026. Based on USDA, NOAA and Colorado State University Extension data. Published by Humblebee.

USDA hardiness zone
8b[1]
Median last spring frost
Apr 8[2]
Median first fall frost
Oct 28[3]
Growing season, median
201 days[4]

Grants Pass, Oregon is in USDA hardiness zone 8b[1]. The median last spring frost at the nearby NOAA station is April 8[2].

Frost dates

JanFebMarAprMayJunJulAugSepOctNovDecLast spring frost: 9 in 10 years after Mar 15, half of years Apr 8, 1 in 10 years after May 1Last frostmedian Apr 8First fall frost: 9 in 10 years before Nov 24, half of years Oct 28, 1 in 10 years before Oct 8First frostmedian Oct 28Frost riskHardyHardy vegetables: plant Mar 11 to Mar 25Mar 11 to Mar 25Semi-hardySemi-hardy vegetables: plant Mar 25 to Apr 8Mar 25 to Apr 8TenderTender vegetables: plant around Apr 8around Apr 8Very tenderVery tender vegetables: plant from Apr 22from Apr 22
Shaded: the span between the dates frost passes in 9 of 10 years and 1 of 10 years[2][3]. Green: planting windows from the CSU rules applied to the median last frost (GardenFacts calculation)[6]. Exact dates are in the tables below.

These dates come from NOAA climate normals for the Grants Pass weather station, at a station close to the city center[5]. The median last spring frost is April 8, so in half of years the last frost comes after that date[2]. In 1 of 10 years the last frost comes after May 1[2]. In the fall, the median first frost is October 28, and in 1 of 10 years it comes before October 8[3]. These are odds from 1991 to 2020 records, not a forecast, so any year can be earlier or later[5].

Frost Likely (9 in 10 years) Even odds (5 in 10) Unlikely (1 in 10)
Last spring frost (32°F)[2] after March 15 after April 8 after May 1
First fall frost (32°F)[3] before October 8 before October 28 before November 24
  • Hard freeze (28°F): median last spring date March 8, median first fall date November 16[7].
  • Frost-free growing season: at least 172 days in 9 of 10 years, 201 days in half of years and 234 days in 1 of 10 years[4].
  • The low reached 32°F or colder in 100% of years and 28°F or colder in 99.6% of years[8].
  • Weather station: Grants Pass (USC00353445), 0.8 miles from the city center, 932 feet, 20 years of 1991 to 2020 records[5].

When to plant vegetables

Colorado State University Extension wrote its planting guide for Colorado, so treat these dates as a starting point[6]. Hardy vegetables such as lettuce, peas and spinach can go in as early as 2 to 4 weeks before the median last frost, which is March 11 to March 25 here[6]. Semi-hardy vegetables such as carrots and potatoes can go in as early as March 25, up to the median date itself[9]. Tender vegetables such as snap beans and sweet corn can be sown from seed around April 8[10]. Very tender vegetables such as tomatoes and peppers typically start 2 or more weeks after the median last frost, so April 22 is the earliest start[11].

  • Hardy (broccoli, cabbage, kohlrabi, lettuce, onions, peas, radishes, spinach, turnips): as early as 2 to 4 weeks before the median last frost (April 8) is March 11 to March 25[6]
  • Semi-hardy (beets, carrots, cauliflower, parsnips, potatoes, Swiss chard): as early as 2 weeks before the median last frost (April 8) is March 25, up to the median date itself[9]
  • Tender (snap beans, sweet corn, cucumbers, summer squash): from seed around the median last frost date, April 8[10]
  • Very tender (cantaloupe, eggplant, peppers, tomatoes, winter squash, watermelon): the earliest start, two weeks after the median last frost (April 8), is April 22[11]
Vegetable (CSU group) Plant from First harvest around
Broccoli (hardy)[12] Mar 11 May 15 (from transplants)
Cabbage (hardy)[12] Mar 11 Jun 4 (from transplants)
Kohlrabi (hardy)[12] Mar 11 Apr 30
Lettuce (hardy)[12] Mar 11 May 10
Onions (hardy)[12] Mar 11 Jun 29
Peas (hardy)[12] Mar 11 May 15
Radishes (hardy)[12] Mar 11 Apr 10
Spinach (hardy)[12] Mar 11 Apr 20
Turnips (hardy)[12] Mar 11 Apr 30
Beets (semi-hardy)[12] Mar 25 May 24
Carrots (semi-hardy)[12] Mar 25 Jun 3
Cauliflower (semi-hardy)[12] Mar 25 not listed
Parsnips (semi-hardy)[12] Mar 25 Jun 3
Potatoes (semi-hardy)[12] Mar 25 Jul 28
Swiss chard (semi-hardy)[12] Mar 25 May 24
Snap beans (tender)[12] Apr 8 Jun 7
Sweet corn (tender)[12] Apr 8 Jun 7
Cucumbers (tender)[12] Apr 8 Jun 2
Summer squash (tender)[12] Apr 8 May 28
Cantaloupe (very tender)[12] Apr 22 Jul 16
Eggplant (very tender)[12] Apr 22 Jun 21 (from transplants)
Peppers (very tender)[12] Apr 22 Jul 1 (from transplants)
Tomatoes (very tender)[12] Apr 22 Jun 26 (from transplants)
Winter squash (very tender)[12] Apr 22 Jul 31
Watermelon (very tender)[12] Apr 22 Jul 16
Spacing, depth and soil temperature (CSU Extension)
Vegetable Min. soil temp Depth Spacing Days to harvest
Broccoli[13] 40°F 1/2 in 18 in 65
Cabbage[13] 40°F 1/2 in 18 in 85
Kohlrabi[13] 40°F 1/2 in 7-9 in 50
Lettuce[13] 35°F 1/4 in 7-9 in 60
Onions[13] 35°F 1/4 in (seed), 1-2 in (sets) 4-6 in 110
Peas[13] 40°F 1 in 4-6 in 65
Radishes[13] 40°F 1/2 in 2-3 in 30
Spinach[13] 40°F 1/2 in 4-6 in 40
Turnips[13] 40°F 1/2 in 4-6 in 50
Beets[13] 40°F 3/4-1 in 4-6 in 60
Carrots[13] 40°F 1/4 in 2-3 in 70
Cauliflower[13] 40°F 1/2 in 18 in –
Parsnips[13] 35°F 1/2 in 5-6 in 70
Potatoes[13] 45°F – – 125
Swiss chard[13] 40°F 1 in 7-9 in 60
Snap beans[13] 55°F 1-1 1/2 in 6 in 60
Sweet corn[13] 50°F 1-1 1/2 in 12 x 30 in or 9 x 36 in 60-90
Cucumbers[13] 60°F 1 in 6 in trellised, 24-36 in untrellised 55
Summer squash[13] 60°F 1-1 1/2 in 36-48 in 50
Cantaloupe[13] 60°F 1-1 1/2 in 36-48 in 85
Eggplant[13] 60°F 1/4 in 18-24 in 60
Peppers[13] 60°F 1/4 in 15-18 in 70
Tomatoes[13] 50°F 1/4 in 24 in trellised 65
Winter squash[13] 60°F 1-1 1/2 in 36-48 in 100
Watermelon[13] 60°F 1-1 1/2 in 36-48 in 85

Hardiness zone

Zone 8b means the average coldest night of the year is 15°F to 20°F, based on 1991 to 2020[1]. The zone is based on winter lows, not on summer heat or frost dates[14]. All of the city's land area lies in ZIP code areas rated zone 8b[15].

Zone 8b: average annual extreme minimum temperature 15°F to 20°F (1991 to 2020)[1]. Modeled value at the city center: 18.6°F[1].

Share of the city's land area by ZIP code zone: zone 8b 100%[15].

All towns in zone 8b and what zone 8b means

Zone by ZIP code
ZIP code Zone Coldest night range
97526[15] 8b 15 to 20°F
97527[15] 8b 15 to 20°F

Questions people ask

What growing zone is Grants Pass, Oregon?
The 2023 USDA map puts the center of Grants Pass in zone 8b[1]. All of the city's land area is in ZIP code areas rated 8b[15].
When is the last frost in Grants Pass?
The median last spring frost is April 8, so in half of years the last frost comes after that date[2]. In 1 of 10 years it comes after May 1[2].
When to plant tomatoes in Grants Pass?
CSU Extension says very tender vegetables like tomatoes typically start 2 or more weeks after the average last frost[11]. Using the median last frost, the earliest start is April 22[11].
When is the first frost in Grants Pass?
The median first fall frost is October 28[3]. In 1 of 10 years the first frost comes before October 8[3].
How long is the growing season in Grants Pass?
The growing season is at least 201 days in half of years[4]. It is at least 172 days in 9 of 10 years[4].

Facts and sources

  1. The 2023 USDA Plant Hardiness Zone Map puts the center of Grants Pass, Oregon in zone 8b. Zone 8b means an average annual extreme minimum temperature of 15°F to 20°F over 1991 to 2020. The map's modeled value at the city center is 18.6°F. USDA zone map 2023 (PRISM, OSU)
  2. Last spring frost (32°F) at this station: in 9 of 10 years the last frost comes after March 15, in half of years after April 8, and in 1 of 10 years after May 1 (NOAA 1991 to 2020 normals). The median last frost date is April 8. NOAA Climate Normals 1991-2020
  3. First fall frost (32°F) at this station: in 1 of 10 years the first frost comes before October 8, in half of years before October 28, and in 9 of 10 years before November 24 (NOAA 1991 to 2020 normals). The median first frost date is October 28. NOAA Climate Normals 1991-2020
  4. Growing season (days between the last spring and first fall 32°F frost) at this station: at least 172 days in 9 of 10 years, at least 201 days in half of years, and at least 234 days in 1 of 10 years. NOAA Climate Normals 1991-2020
  5. Frost dates on this page come from NOAA climate normals for the Grants Pass weather station (USC00353445), 0.8 miles from the center of Grants Pass at 932 feet, using 20 years of records from 1991 to 2020. NOAA Climate Normals 1991-2020
  6. Colorado State University Extension's vegetable planting guide (written for Colorado) groups broccoli, cabbage, kohlrabi, lettuce, onions, peas, radishes, spinach, turnips as hardy vegetables, with this rule: as early as 2-4 weeks before the average last... CSU Extension GardenNotes #720
  7. Hard freeze (28°F) at this station: the median last spring date is March 8 and the median first fall date is November 16. NOAA Climate Normals 1991-2020
  8. At this station the low reached 32°F or colder in 100% of years from 1991 to 2020, and 28°F or colder in 99.6% of years. NOAA Climate Normals 1991-2020
  9. Colorado State University Extension's vegetable planting guide (written for Colorado) groups beets, carrots, cauliflower, parsnips, potatoes, Swiss chard as semi-hardy vegetables, with this rule: as early as 0-2 weeks before the average last spring frost.... CSU Extension GardenNotes #720
  10. Colorado State University Extension's vegetable planting guide (written for Colorado) groups snap beans, sweet corn, cucumbers, summer squash as tender vegetables, with this rule: from seed around the average last spring frost; cucumber and summer squash... CSU Extension GardenNotes #720
  11. Colorado State University Extension's vegetable planting guide (written for Colorado) groups cantaloupe, eggplant, peppers, tomatoes, winter squash, watermelon as very tender vegetables, with this rule: typically 2 or more weeks after the average last... CSU Extension GardenNotes #720
  12. GardenFacts calculation: earliest planting date plus CSU days to harvest (table on this page), from the station's median last frost. NOAA Climate Normals 1991-2020
  13. CSU Extension vegetable table: soil temperature, depth, spacing, days to harvest (table on this page). CSU Extension GardenNotes #720
  14. USDA hardiness zones are based on the average annual extreme minimum winter temperature (the coldest night of each winter, averaged over 1991 to 2020 for the 2023 map), not on summer heat or frost dates. Each zone spans 10°F and each half zone (a or b)... USDA Plant Hardiness Zone Map
  15. Grants Pass, Oregon overlaps 2 ZIP code areas. By land area, 100% lies in ZIP code areas rated zone 8b. USDA zone map 2023 (PRISM, OSU)

Frost dates are probabilities from 1991 to 2020 weather records at one NOAA station, not a forecast. Any year can be earlier or later. The hardiness zone describes the average coldest winter night, not frost dates or summer heat. Spots inside the city can differ (ZIP table). Planting rules come from Colorado State University Extension's guide, written for Colorado. A local extension office may give dates tuned to the area. Planting and harvest dates marked GardenFacts calculation are simple arithmetic from the facts above, not advice from the source.

Hardiness zone data: USDA Plant Hardiness Zone Map (2023), USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu, accessed October 30, 2026. This is not the official USDA map. Frost data: NOAA NCEI U.S. Climate Normals 1991-2020. Planting rules: Colorado State University Extension.