USDA Hardiness Zone 8a
Frost Dates for 97530 — Jacksonville, Oregon
NOAA 1991–2020 normals from Ruch, OR (1,550 ft), under a mile southwest.
Updated
In Jacksonville, the last spring frost (32°F) is around May 4 in half of years and has passed by May 23 in nine years out of ten. The first fall frost comes around October 13, as early as September 22 one year in ten, leaving a typical freeze-free season of 160 days (NOAA, Ruch, OR).
- Last spring frost
- May 4
- First fall frost
- October 13
- Growing season
- 160 days
- Hardiness zone
- 8a
50% probability
50% probability
freeze-free, 50%
10 to 15°F (-12.2 to -9.4°C) coldest night
- First snow
- Rare
- Last snow
- Rare
- Winters with snow
- 12%
- Snow per year
- 0.3"
median, 1991–2020
median, 1991–2020
2 of 17 observed
NOAA normal
Frost risk by date in Jacksonville
Half of springs at Ruch, OR see their last 32°F night by May 4; only one in ten is past it by April 15, and one in ten still has one after May 23. Planting tender crops after May 11 leaves a 30% risk of a frost on them, after May 16 20%, and after May 23 10%. The 19 days between the even-odds date and the one-in-ten date is narrower than at 70% of the 103 Oregon stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 13 in half of years, as early as September 22 one year in ten, and holds off past October 30 one year in ten. A hard freeze of 28°F follows 19 days later, around November 1; in spring the one-in-ten date for 28°F is May 2, 21 days before the 32°F one. The freeze-free season lasts 160 days in a typical year, shorter than at 76% of the 103 Oregon stations; it reaches 187 days one year in ten and falls short of 132 one year in ten. On average 103 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 21 days longer, to about May 25, and return around September 26. Nights of 24°F, cold enough to damage hardier plants, come in 100% of winters and 16°F in 41%.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 5 | May 12 | May 16 | May 21 | May 25 | May 29 | Jun 2 | Jun 6 | Jun 15 |
| 32°F | Apr 15 | Apr 22 | Apr 27 | Apr 30 | May 4 | May 7 | May 11 | May 16 | May 23 |
| 28°F | Mar 12 | Mar 21 | Mar 29 | Apr 2 | Apr 6 | Apr 12 | Apr 18 | Apr 25 | May 2 |
| 24°F | Jan 31 | Feb 13 | Feb 22 | Feb 28 | Mar 4 | Mar 10 | Mar 18 | Mar 25 | Apr 1 |
| 20°F88% of yrs | Dec 12 | Dec 26 | Jan 3 | Jan 12 | Jan 25 | Feb 2 | Feb 11 | Feb 21 | Feb 28 |
| 16°F41% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 5 | Sep 12 | Sep 17 | Sep 21 | Sep 26 | Oct 1 | Oct 4 | Oct 7 | Oct 14 |
| 32°F | Sep 22 | Sep 29 | Oct 4 | Oct 9 | Oct 13 | Oct 16 | Oct 21 | Oct 25 | Oct 30 |
| 28°F | Oct 8 | Oct 18 | Oct 23 | Oct 28 | Nov 1 | Nov 3 | Nov 8 | Nov 14 | Nov 23 |
| 24°F | Oct 29 | Nov 3 | Nov 9 | Nov 14 | Nov 20 | Nov 26 | Dec 1 | Dec 9 | Dec 22 |
| 20°F88% of yrs | Nov 9 | Nov 21 | Nov 29 | Dec 4 | Dec 11 | Dec 19 | Dec 28 | Jan 7 | Jan 24 |
| 16°F41% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Ruch, 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 97530 →Compare Jacksonville with another place →
Weather by month in Jacksonville
July is the warmest month at Ruch, OR, averaging 92°F by day and 52°F at night; December is the coldest at 49°F and 30°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 57% of years.
Warmth for growing adds up to 2,844 growing degree days a year (base 50°F), more than at 86% of the 103 Oregon stations. 30% of them (852) have built up by the end of June, and July adds the most, 682. Precipitation totals 27.4 inches a year, most in December (5.1") and least in August (0.4"); May to September bring 13% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 50 | 30 | 4.4 | 100% | 20 | 2 |
| Feb | 55 | 31 | 3.0 | 100% | 18 | 9 |
| Mar | 60 | 33 | 3.0 | 100% | 15 | 33 |
| Apr | 65 | 36 | 2.1 | 97% | 7 | 92 |
| May | 75 | 42 | 1.4 | 57% | 2 | 273 |
| Jun | 82 | 47 | 0.7 | 5% | <1 | 443 |
| Jul | 92 | 52 | 0.5 | 0% | 0 | 682 |
| Aug | 91 | 51 | 0.4 | 0% | 0 | 653 |
| Sep | 85 | 45 | 0.6 | 21% | 1 | 446 |
| Oct | 72 | 38 | 2.3 | 90% | 7 | 185 |
| Nov | 56 | 33 | 3.9 | 100% | 14 | 23 |
| Dec | 49 | 30 | 5.1 | 100% | 20 | 4 |
Monthly normals 1991–2020 at Ruch, OR (1,550 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, Medford Rogue Vly Airport, OR, 14 miles northeast of Jacksonville and 253 feet lower, has a last frost 26 days earlier (April 8), a first frost 16 days later (October 29), a season 44 days longer.
When it snows in Jacksonville, Oregon
Measurable snow is rare here: only 2 of 17 winters from 1991 to 2020 recorded 0.1 inch or more at Applegate, OR, 6.9 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 97530
| When | What to do |
|---|---|
| February 23 – March 9 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 9 – March 23 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 6 – April 20 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 4 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 21 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 29 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 13 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 97530 is under a mile from Ruch, OR, which stands at 1,550 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 97530 in zone 8a, the band where the coldest night of the year averaged 10 to 15°F (-12.2 to -9.4°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.