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Frost dates and planting calendar for Pittsburgh, Pennsylvania

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

USDA hardiness zone
6b[1]
Median last spring frost
May 2[2]
Median first fall frost
Oct 20[3]
Growing season, median
170 days[4]

The 2023 USDA map puts the center of Pittsburgh in hardiness zone 6b[1]. NOAA records from a nearby station put the median last spring frost on May 2[2].

Frost dates

JanFebMarAprMayJunJulAugSepOctNovDecLast spring frost: 9 in 10 years after Apr 17, half of years May 2, 1 in 10 years after May 20Last frostmedian May 2First fall frost: 9 in 10 years before Nov 3, half of years Oct 20, 1 in 10 years before Oct 1First frostmedian Oct 20Frost riskHardyHardy vegetables: plant Apr 4 to Apr 18Apr 4 to Apr 18Semi-hardySemi-hardy vegetables: plant Apr 18 to May 2Apr 18 to May 2TenderTender vegetables: plant around May 2around May 2Very tenderVery tender vegetables: plant from May 16from May 16
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.

Frost dates here come from NOAA climate normals for the Mckeesport weather station near Pittsburgh[5]. They are odds from 1991 to 2020 records, not a forecast[5]. In half of years the last spring frost comes after May 2, and in 1 of 10 years it comes after May 20[2]. In fall, the first frost comes before October 20 in half of years and before October 1 in 1 of 10 years[3]. In half of years the growing season lasts at least 170 days[4].

Frost Likely (9 in 10 years) Even odds (5 in 10) Unlikely (1 in 10)
Last spring frost (32°F)[2] after April 17 after May 2 after May 20
First fall frost (32°F)[3] before October 1 before October 20 before November 3
  • Hard freeze (28°F): median last spring date April 20, median first fall date November 1[7].
  • Frost-free growing season: at least 144 days in 9 of 10 years, 170 days in half of years and 192 days in 1 of 10 years[4].
  • The low reached 32°F or colder in 100% of years and 28°F or colder in 100% of years[8].
  • Weather station: Mckeesport (USC00365573), 9.2 miles from the city center, 740 feet, 25 years of 1991 to 2020 records[5].

When to plant vegetables

The planting dates below use Colorado State University Extension's vegetable guide, which was written for Colorado[6]. GardenFacts takes the NOAA median last frost, May 2, as the average last frost[6]. Hardy crops like peas, lettuce and spinach can go in as early as April 4 to April 18[6]. Semi-hardy crops like carrots, beets and potatoes can go in as early as April 18, up to May 2[9]. Tender crops like snap beans and sweet corn go in from seed around May 2[10], and very tender crops like tomatoes and peppers typically wait 2 or more weeks after the average last frost, with May 16 as 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 (May 2) is April 4 to April 18[6]
  • Semi-hardy (beets, carrots, cauliflower, parsnips, potatoes, Swiss chard): as early as 2 weeks before the median last frost (May 2) is April 18, up to the median date itself[9]
  • Tender (snap beans, sweet corn, cucumbers, summer squash): from seed around the median last frost date, May 2[10]
  • Very tender (cantaloupe, eggplant, peppers, tomatoes, winter squash, watermelon): the earliest start, two weeks after the median last frost (May 2), is May 16[11]
Vegetable (CSU group) Plant from First harvest around
Broccoli (hardy)[12] Apr 4 Jun 8 (from transplants)
Cabbage (hardy)[12] Apr 4 Jun 28 (from transplants)
Kohlrabi (hardy)[12] Apr 4 May 24
Lettuce (hardy)[12] Apr 4 Jun 3
Onions (hardy)[12] Apr 4 Jul 23
Peas (hardy)[12] Apr 4 Jun 8
Radishes (hardy)[12] Apr 4 May 4
Spinach (hardy)[12] Apr 4 May 14
Turnips (hardy)[12] Apr 4 May 24
Beets (semi-hardy)[12] Apr 18 Jun 17
Carrots (semi-hardy)[12] Apr 18 Jun 27
Cauliflower (semi-hardy)[12] Apr 18 not listed
Parsnips (semi-hardy)[12] Apr 18 Jun 27
Potatoes (semi-hardy)[12] Apr 18 Aug 21
Swiss chard (semi-hardy)[12] Apr 18 Jun 17
Snap beans (tender)[12] May 2 Jul 1
Sweet corn (tender)[12] May 2 Jul 1
Cucumbers (tender)[12] May 2 Jun 26
Summer squash (tender)[12] May 2 Jun 21
Cantaloupe (very tender)[12] May 16 Aug 9
Eggplant (very tender)[12] May 16 Jul 15 (from transplants)
Peppers (very tender)[12] May 16 Jul 25 (from transplants)
Tomatoes (very tender)[12] May 16 Jul 20 (from transplants)
Winter squash (very tender)[12] May 16 Aug 24
Watermelon (very tender)[12] May 16 Aug 9
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

Pittsburgh's zone 6b means an average coldest winter night of -5°F to 0°F over 1991 to 2020[1]. The zone is about winter cold, not summer heat or frost dates[14]. USDA describes the map as the standard gardeners use to judge which perennial plants are most likely to thrive[14]. The city spans two zones: by land area, 86% lies in ZIP code areas rated 6b and 14% in areas rated 7a[15].

Zone 6b: average annual extreme minimum temperature -5°F to 0°F (1991 to 2020)[1]. Modeled value at the city center: -0.5°F[1].

Share of the city's land area by ZIP code zone: zone 6b 86%, zone 7a 14%[15].

All towns in zone 6b and what zone 6b means

Zone by ZIP code
ZIP code Zone Coldest night range
15206[15] 6b -5 to 0°F
15212[15] 6b -5 to 0°F
15207[15] 6b -5 to 0°F
15210[15] 6b -5 to 0°F
15217[15] 6b -5 to 0°F
15214[15] 6b -5 to 0°F
15213[15] 6b -5 to 0°F
15220[15] 6b -5 to 0°F
15219[15] 6b -5 to 0°F
15205[15] 6b -5 to 0°F
15226[15] 6b -5 to 0°F
15201[15] 7a 0 to 5°F
15204[15] 7a 0 to 5°F
15216[15] 6b -5 to 0°F
15211[15] 6b -5 to 0°F
15224[15] 6b -5 to 0°F
15208[15] 6b -5 to 0°F
15203[15] 7a 0 to 5°F
15233[15] 7a 0 to 5°F
15236[15] 6b -5 to 0°F
15221[15] 6b -5 to 0°F
15222[15] 7a 0 to 5°F
15232[15] 6b -5 to 0°F
15120[15] 6b -5 to 0°F
15218[15] 6b -5 to 0°F
15227[15] 6b -5 to 0°F
15234[15] 6b -5 to 0°F
15106[15] 6b -5 to 0°F
15215[15] 6b -5 to 0°F
15282[15] 6b -5 to 0°F

Questions people ask

What growing zone is Pittsburgh?
The 2023 USDA map puts the center of Pittsburgh in zone 6b[1]. By land area, 14% of the city lies in ZIP code areas rated zone 7a[15].
When is the last frost in Pittsburgh?
At the Mckeesport station, the median last spring frost is May 2[2]. In 1 of 10 years the last frost comes after May 20[2].
When to plant tomatoes in Pittsburgh?
CSU Extension says tomatoes typically go in 2 or more weeks after the average last frost[11]. For Pittsburgh that makes May 16 the earliest start[11].
When is the first frost in Pittsburgh?
The median first fall frost is October 20[3]. In 1 of 10 years it comes before October 1[3].
How long is the growing season in Pittsburgh?
In half of years the season between the last spring and first fall frost is at least 170 days[4]. In 9 of 10 years it is at least 144 days[4].

Facts and sources

  1. The 2023 USDA Plant Hardiness Zone Map puts the center of Pittsburgh, Pennsylvania in zone 6b. Zone 6b means an average annual extreme minimum temperature of -5°F to 0°F over 1991 to 2020. The map's modeled value at the city center is minus 0.5°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 April 17, in half of years after May 2, and in 1 of 10 years after May 20 (NOAA 1991 to 2020 normals). The median last frost date is May 2. 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 1, in half of years before October 20, and in 9 of 10 years before November 3 (NOAA 1991 to 2020 normals). The median first frost date is October 20. NOAA Climate Normals 1991-2020
  4. Growing season (days between the last spring and first fall 32°F frost) at this station: at least 144 days in 9 of 10 years, at least 170 days in half of years, and at least 192 days in 1 of 10 years. NOAA Climate Normals 1991-2020
  5. Frost dates on this page come from NOAA climate normals for the Mckeesport weather station (USC00365573), 9.2 miles from the center of Pittsburgh at 740 feet, using 25 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 April 20 and the median first fall date is November 1. 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 100% 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. Pittsburgh, Pennsylvania overlaps 33 ZIP code areas. By land area, 86% lies in ZIP code areas rated zone 6b, 14% lies in ZIP code areas rated zone 7a. 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.