USDA Hardiness Zone 6b
Frost Dates for 97760 — Terrebonne, Oregon
NOAA 1991–2020 normals from Redmond Roberts Field, OR (3,043 ft), 9 miles south.
Updated
In Terrebonne, the last spring frost (32°F) is around June 9 in half of years and has passed by June 26 in nine years out of ten. The first fall frost comes around September 14, as early as September 1 one year in ten, leaving a typical freeze-free season of 98 days (NOAA, Redmond Roberts Field, OR).
- Last spring frost
- June 9
- First fall frost
- September 14
- Growing season
- 98 days
- Hardiness zone
- 6b
50% probability
50% probability
freeze-free, 50%
-5 to 0°F (-20.6 to -17.8°C) coldest night
- First snow
- November 18
- Last snow
- February 15
- Winters with snow
- 100%
- Snow per year
- 21.2"
median, 1991–2020
median, 1991–2020
17 of 17 observed
NOAA normal
Frost risk by date in Terrebonne
Half of springs at Redmond Roberts Field, OR see their last 32°F night by June 9; only one in ten is past it by May 17, and one in ten still has one after June 26. Planting tender crops after June 17 leaves a 30% risk of a frost on them, after June 21 20%, and after June 26 10%. The 17 days between the even-odds date and the one-in-ten date is narrower than at 83% of the 103 Oregon stations behind this site's ZIP pages.
In fall the first 32°F night comes by September 14 in half of years, as early as September 1 one year in ten, and holds off past October 1 one year in ten. A hard freeze of 28°F follows 16 days later, around September 30; in spring the one-in-ten date for 28°F is June 9, 17 days before the 32°F one. The freeze-free season lasts 98 days in a typical year, shorter than at 97% of the 103 Oregon stations; it reaches 124 days one year in ten and falls short of 73 one year in ten. On average 181 nights a year drop to 32°F or below. Severe cold of 16°F or below comes every winter, usually between November 11 and March 17.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | too rare for a date | ||||||||
| 32°F | May 17 | May 25 | May 31 | Jun 4 | Jun 9 | Jun 13 | Jun 17 | Jun 21 | Jun 26 |
| 28°F | Apr 28 | May 3 | May 6 | May 10 | May 14 | May 19 | May 25 | May 31 | Jun 9 |
| 24°F | Apr 9 | Apr 17 | Apr 22 | Apr 25 | Apr 28 | May 1 | May 4 | May 8 | May 14 |
| 20°F | Mar 14 | Mar 24 | Mar 30 | Apr 4 | Apr 9 | Apr 14 | Apr 18 | Apr 23 | Apr 29 |
| 16°F | Feb 13 | Feb 25 | Mar 4 | Mar 10 | Mar 17 | Mar 23 | Mar 29 | Apr 3 | Apr 12 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | too rare for a date | ||||||||
| 32°F | Sep 1 | Sep 5 | Sep 8 | Sep 12 | Sep 14 | Sep 19 | Sep 22 | Sep 26 | Oct 1 |
| 28°F | Sep 14 | Sep 20 | Sep 23 | Sep 27 | Sep 30 | Oct 3 | Oct 5 | Oct 10 | Oct 15 |
| 24°F | Sep 29 | Oct 3 | Oct 6 | Oct 9 | Oct 13 | Oct 17 | Oct 19 | Oct 24 | Oct 30 |
| 20°F | Oct 8 | Oct 14 | Oct 18 | Oct 22 | Oct 26 | Oct 30 | Nov 2 | Nov 8 | Nov 17 |
| 16°F | Oct 20 | Oct 28 | Nov 1 | Nov 5 | Nov 11 | Nov 17 | Nov 21 | Nov 26 | Dec 3 |
Freeze probabilities 1991–2020 at Redmond Roberts Field, 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 97760 →Compare Terrebonne with another place →
Weather by month in Terrebonne
July is the warmest month at Redmond Roberts Field, OR, averaging 88°F by day and 49°F at night; December is the coldest at 42°F and 23°F. A freezing night is all but certain in every month from October to May (a 90% chance or more). From July to August the chance of a 32°F night stays under 10% each month. In spring, June still brings one in 66% of years.
Warmth for growing adds up to 1,969 growing degree days a year (base 50°F), fewer than at 63% of the 103 Oregon stations. 26% of them (503) have built up by the end of June, and July adds the most, 558. Precipitation totals 8.6 inches a year, most in May (1.2") and least in July (0.4"); May to September bring 36% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 44 | 25 | 1.0 | 100% | 26 | 1 |
| Feb | 48 | 25 | 0.7 | 100% | 24 | 2 |
| Mar | 55 | 28 | 0.6 | 100% | 26 | 8 |
| Apr | 60 | 31 | 0.7 | 100% | 21 | 33 |
| May | 69 | 38 | 1.2 | 99% | 10 | 154 |
| Jun | 77 | 43 | 0.6 | 66% | 3 | 306 |
| Jul | 88 | 49 | 0.4 | 5% | <1 | 558 |
| Aug | 87 | 47 | 0.5 | 9% | <1 | 523 |
| Sep | 79 | 41 | 0.4 | 89% | 5 | 298 |
| Oct | 65 | 33 | 0.7 | 100% | 18 | 75 |
| Nov | 51 | 28 | 0.8 | 100% | 22 | 12 |
| Dec | 42 | 23 | 1.0 | 100% | 27 | 1 |
Monthly normals 1991–2020 at Redmond Roberts Field, OR (3,043 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, Prineville, OR, 19 miles east of Terrebonne and 167 feet lower, has a last frost 8 days earlier (June 1), a first frost 8 days later (September 22), a season 15 days longer.
When it snows in Terrebonne, Oregon
The first measurable snow (0.1 inch or more) in Terrebonne usually arrives around November 18, and the last of the season around February 15. Those are the middle dates across the winters of 1991–2020 at Grizzly, OR, 15.9 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 114 days after the last snow.
Planting calendar for 97760
| When | What to do |
|---|---|
| March 31 – April 14 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| April 14 – April 28 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| May 12 – May 26 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| June 9 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by June 22 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by August 31 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| September 14 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 97760 is 9 miles from Redmond Roberts Field, OR, which stands at 3,043 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 3 other ZIP codes share the station; its figures are presented in full for 97756 (Redmond). The 2023 USDA Plant Hardiness Zone Map lists ZIP 97760 in zone 6b, the band where the coldest night of the year averaged -5 to 0°F (-20.6 to -17.8°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.