USDA Hardiness Zone 8b
Frost Dates for 97457 — Myrtle Creek, Oregon
NOAA 1991–2020 normals from Riddle, OR (680 ft), 9 miles southwest.
Updated
In Myrtle Creek, the last spring frost (32°F) is around March 31 in half of years and has passed by April 27 in nine years out of ten. The first fall frost comes around November 6, as early as October 11 one year in ten, leaving a typical freeze-free season of 221 days (NOAA, Riddle, OR).
- Last spring frost
- March 31
- First fall frost
- November 6
- Growing season
- 221 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
- 47%
- Snow per year
- 4.2"
median, 1991–2020
median, 1991–2020
8 of 17 observed
NOAA normal
Frost risk by date in Myrtle Creek
Half of springs at Riddle, OR see their last 32°F night by March 31; only one in ten is past it by February 27, and one in ten still has one after April 27. Planting tender crops after April 11 leaves a 30% risk of a frost on them, after April 18 20%, and after April 27 10%. The 27 days between the even-odds date and the one-in-ten date is wider than at 75% 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 November 6 in half of years, as early as October 11 one year in ten, and holds off past December 13 one year in ten. A hard freeze of 28°F follows 34 days later, around December 10; in spring the one-in-ten date for 28°F is March 31, 27 days before the 32°F one. The freeze-free season lasts 221 days in a typical year, longer than at 65% of the 103 Oregon stations; it reaches 266 days one year in ten and falls short of 184 one year in ten. On average 33 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 27 days longer, to about April 27, and return around October 14. A 24°F night is unusual: 48% of winters had one.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 8 | Apr 14 | Apr 20 | Apr 23 | Apr 27 | Apr 30 | May 4 | May 9 | May 14 |
| 32°F | Feb 27 | Mar 10 | Mar 20 | Mar 26 | Mar 31 | Apr 5 | Apr 11 | Apr 18 | Apr 27 |
| 28°F93% of yrs | Dec 22 | Jan 14 | Feb 1 | Feb 14 | Feb 20 | Feb 28 | Mar 7 | Mar 18 | Mar 31 |
| 24°F48% of yrs | too rare for a date | ||||||||
| 20°F15% of yrs | too rare for a date | ||||||||
| 16°F6% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 28 | Oct 1 | Oct 6 | Oct 10 | Oct 14 | Oct 18 | Oct 24 | Oct 30 | Nov 7 |
| 32°F | Oct 11 | Oct 20 | Oct 26 | Oct 31 | Nov 6 | Nov 15 | Nov 25 | Dec 4 | Dec 13 |
| 28°F93% of yrs | Oct 28 | Nov 7 | Nov 19 | Dec 2 | Dec 10 | Dec 22 | Jan 1 | Jan 15 | Feb 12 |
| 24°F48% of yrs | too rare for a date | ||||||||
| 20°F15% of yrs | too rare for a date | ||||||||
| 16°F6% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Riddle, 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 97457 →Compare Myrtle Creek with another place →
Weather by month in Myrtle Creek
July is the warmest month at Riddle, OR, averaging 88°F by day and 55°F at night; December is the coldest at 51°F and 37°F. From May to September the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 85% of years and March still brings one in 79% of years and April still brings one in 44% of years.
Warmth for growing adds up to 3,153 growing degree days a year (base 50°F), more than at 95% of the 103 Oregon stations. 33% of them (1,031) have built up by the end of June, and July adds the most, 674. Precipitation totals 31.3 inches a year, most in December (6.2") and least in July (0.3"); May to September bring 13% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 53 | 37 | 4.7 | 84% | 8 | 12 |
| Feb | 57 | 37 | 3.4 | 85% | 6 | 30 |
| Mar | 62 | 39 | 3.4 | 79% | 5 | 73 |
| Apr | 66 | 41 | 2.5 | 44% | 1 | 141 |
| May | 74 | 47 | 1.9 | 6% | <1 | 316 |
| Jun | 80 | 51 | 1.0 | 0% | 0 | 459 |
| Jul | 88 | 55 | 0.3 | 0% | 0 | 674 |
| Aug | 89 | 54 | 0.3 | 0% | 0 | 663 |
| Sep | 84 | 49 | 0.7 | 0% | 0 | 482 |
| Oct | 71 | 43 | 2.3 | 41% | 2 | 233 |
| Nov | 58 | 41 | 4.6 | 61% | 4 | 58 |
| Dec | 51 | 37 | 6.2 | 87% | 7 | 12 |
Monthly normals 1991–2020 at Riddle, OR (680 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, Roseburg Kqen, OR, 14 miles northwest of Myrtle Creek and 255 feet lower, has a last frost 8 days earlier (March 23), a first frost 12 days later (November 18), a season 16 days longer.
When it snows in Myrtle Creek, Oregon
Measurable snow is rare here: only 8 of 17 winters from 1991 to 2020 recorded 0.1 inch or more at Myrtle Creek 8 NE, OR, 4.7 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 97457
| When | What to do |
|---|---|
| January 20 – February 3 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 3 – February 17 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 3 – March 17 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| March 31 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 14 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 23 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| November 6 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 97457 is 9 miles from Riddle, OR, which stands at 680 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 97457 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.