USDA Hardiness Zone 8b
Frost Dates for 97219 — Portland, Oregon
NOAA 1991–2020 normals from Portland Kgw-Tv, OR (159 ft), 4 miles north.
Updated
In Portland, the last spring frost (32°F) is around February 25 in half of years and has passed by March 21 in nine years out of ten. The first fall frost comes around December 1, as early as November 10 one year in ten, leaving a typical freeze-free season of 280 days (NOAA, Portland Kgw-Tv, OR).
- Last spring frost
- February 25
- First fall frost
- December 1
- Growing season
- 280 days
- Hardiness zone
- 8b
50% probability
50% probability
freeze-free, 50%
15 to 20°F (-9.4 to -6.7°C) coldest night
- First snow
- Rare
- Last snow
- Rare
- Winters with snow
- 25%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
4 of 16 observed
NOAA normal
Frost risk by date in Portland
Half of springs at Portland Kgw-Tv, OR see their last 32°F night by February 25; only one in ten is past it by January 24, and one in ten still has one after March 21. Planting tender crops after March 6 leaves a 30% risk of a frost on them, after March 13 20%, and after March 21 10%. The 24 days between the even-odds date and the one-in-ten date is wider than at 60% of the 103 Oregon stations behind this site's ZIP pages, so a fixed calendar date is a gamble here.
In fall the first 32°F night comes by December 1 in half of years, as early as November 10 one year in ten, and holds off past December 27 one year in ten. A hard freeze of 28°F follows 19 days later, around December 20; in spring the one-in-ten date for 28°F is February 26, 23 days before the 32°F one. The freeze-free season lasts 280 days in a typical year, longer than at 94% of the 103 Oregon stations; it reaches 318 days one year in ten and falls short of 245 one year in ten. On average 18 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 32 days longer, to about March 29, and return around November 12. A 24°F night is unusual: 49% of winters had one.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Mar 7 | Mar 14 | Mar 20 | Mar 25 | Mar 29 | Apr 1 | Apr 5 | Apr 13 | Apr 21 |
| 32°F | Jan 24 | Feb 3 | Feb 11 | Feb 18 | Feb 25 | Feb 28 | Mar 6 | Mar 13 | Mar 21 |
| 28°F86% of yrs | Dec 21 | Jan 3 | Jan 14 | Jan 23 | Jan 31 | Feb 4 | Feb 10 | Feb 18 | Feb 26 |
| 24°F49% of yrs | too rare for a date | ||||||||
| 20°F19% of yrs | too rare for a date | ||||||||
| 16°F5% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 28 | Nov 2 | Nov 6 | Nov 10 | Nov 12 | Nov 16 | Nov 21 | Nov 25 | Dec 1 |
| 32°F | Nov 10 | Nov 16 | Nov 22 | Nov 26 | Dec 1 | Dec 5 | Dec 11 | Dec 18 | Dec 27 |
| 28°F86% of yrs | Nov 25 | Dec 2 | Dec 7 | Dec 13 | Dec 20 | Dec 27 | Jan 3 | Jan 13 | Jan 30 |
| 24°F49% of yrs | too rare for a date | ||||||||
| 20°F19% of yrs | too rare for a date | ||||||||
| 16°F5% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Portland Kgw-Tv, OR, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.
Frost risk on any date in 97219 →Compare Portland with another place →
Weather by month in Portland
August is the warmest month at Portland Kgw-Tv, OR, averaging 81°F by day and 59°F at night; December is the coldest at 46°F and 37°F. From April to October the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 74% of years and March still brings one in 38% of years.
Warmth for growing adds up to 2,697 growing degree days a year (base 50°F), more than at 76% of the 103 Oregon stations. 31% of them (830) have built up by the end of June, and August adds the most, 608. Precipitation totals 44.1 inches a year, most in December (7.4") and least in July (0.4"); May to September bring 15% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 47 | 37 | 6.4 | 86% | 5 | 5 |
| Feb | 51 | 39 | 4.7 | 74% | 4 | 12 |
| Mar | 56 | 41 | 4.8 | 38% | 1 | 42 |
| Apr | 61 | 44 | 3.6 | 2% | 0 | 105 |
| May | 68 | 49 | 2.6 | 0% | 0 | 274 |
| Jun | 73 | 53 | 1.5 | 0% | 0 | 393 |
| Jul | 80 | 58 | 0.4 | 0% | 0 | 592 |
| Aug | 81 | 59 | 0.5 | 0% | 0 | 608 |
| Sep | 75 | 55 | 1.6 | 0% | 0 | 450 |
| Oct | 63 | 48 | 4.0 | 1% | <1 | 183 |
| Nov | 52 | 42 | 6.6 | 46% | 2 | 29 |
| Dec | 46 | 37 | 7.4 | 88% | 5 | 5 |
Monthly normals 1991–2020 at Portland Kgw-Tv, OR (159 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.
Compared with the next station
The nearest other station, Beaverton 2 SSW, OR, 6 miles west of Portland, has a last frost 35 days later (April 1), a first frost 25 days earlier (November 6), a season 58 days shorter.
When it snows in Portland, Oregon
Measurable snow is rare here: only 4 of 16 winters from 1991 to 2020 recorded 0.1 inch or more at Beaverton 2 SSW, OR, 5.5 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 97219
| When | What to do |
|---|---|
| December 17 – December 31 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| December 31 – January 14 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| January 28 – February 11 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| February 25 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by September 8 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by November 17 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| December 1 onward | Plant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter. |
The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.
Where these figures come from
ZIP 97219 is 4 miles from Portland Kgw-Tv, OR, which stands at 159 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 13 other ZIP codes share the station; its figures are presented in full for 97206 (Portland). The 2023 USDA Plant Hardiness Zone Map lists ZIP 97219 in zone 8b, the band where the coldest night of the year averaged 15 to 20°F (-9.4 to -6.7°C) over 1991–2020; a zone describes winter lows, not frost dates.
Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.
Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.