USDA Hardiness Zone 7b
Frost Dates for 38581 — Rock Island, Tennessee
NOAA 1991–2020 normals from Rock Island Sp, TN (880 ft), 4 miles north.
Updated
In Rock Island, the last spring frost (32°F) is around April 6 in half of years and has passed by April 22 in nine years out of ten. The first fall frost comes around October 30, as early as October 17 one year in ten, leaving a typical freeze-free season of 207 days (NOAA, Rock Island Sp, TN).
- Last spring frost
- April 6
- First fall frost
- October 30
- Growing season
- 207 days
- Hardiness zone
- 7b
50% probability
50% probability
freeze-free, 50%
5 to 10°F (-15.0 to -12.2°C) coldest night
- First snow
- January 7
- Last snow
- February 17
- Winters with snow
- 95%
- Snow per year
- 4.1"
median, 1991–2020
median, 1991–2020
21 of 22 observed
NOAA normal
Frost risk by date in Rock Island
Half of springs at Rock Island Sp, TN see their last 32°F night by April 6; only one in ten is past it by March 22, and one in ten still has one after April 22. Planting tender crops after April 12 leaves a 30% risk of a frost on them, after April 16 20%, and after April 22 10%. The 16 days between the even-odds date and the one-in-ten date is narrower than at 53% of the 144 Tennessee stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 30 in half of years, as early as October 17 one year in ten, and holds off past November 14 one year in ten. A hard freeze of 28°F follows 10 days later, around November 9; in spring the one-in-ten date for 28°F is April 9, 13 days before the 32°F one. The freeze-free season lasts 207 days in a typical year, longer than at 59% of the 144 Tennessee stations; it reaches 230 days one year in ten and falls short of 187 one year in ten. On average 74 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 12 days longer, to about April 18, and return around October 21. Severe cold of 16°F or below comes in 97% of winters, usually between December 27 and February 12.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 4 | Apr 9 | Apr 12 | Apr 16 | Apr 18 | Apr 22 | Apr 25 | Apr 29 | May 3 |
| 32°F | Mar 22 | Mar 28 | Mar 31 | Apr 3 | Apr 6 | Apr 8 | Apr 12 | Apr 16 | Apr 22 |
| 28°F | Mar 8 | Mar 15 | Mar 19 | Mar 23 | Mar 26 | Mar 30 | Apr 1 | Apr 5 | Apr 9 |
| 24°F | Feb 20 | Feb 28 | Mar 4 | Mar 8 | Mar 13 | Mar 17 | Mar 21 | Mar 25 | Mar 31 |
| 20°F | Feb 1 | Feb 10 | Feb 17 | Feb 23 | Feb 28 | Mar 2 | Mar 8 | Mar 14 | Mar 20 |
| 16°F97% of yrs | Jan 16 | Jan 28 | Feb 2 | Feb 6 | Feb 12 | Feb 18 | Feb 24 | Mar 1 | Mar 8 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 10 | Oct 13 | Oct 16 | Oct 19 | Oct 21 | Oct 24 | Oct 27 | Oct 30 | Nov 4 |
| 32°F | Oct 17 | Oct 21 | Oct 25 | Oct 27 | Oct 30 | Nov 1 | Nov 5 | Nov 8 | Nov 14 |
| 28°F | Oct 26 | Oct 31 | Nov 2 | Nov 5 | Nov 9 | Nov 13 | Nov 16 | Nov 21 | Nov 28 |
| 24°F | Nov 5 | Nov 10 | Nov 15 | Nov 19 | Nov 23 | Nov 27 | Dec 1 | Dec 5 | Dec 14 |
| 20°F | Nov 17 | Nov 24 | Nov 29 | Dec 3 | Dec 7 | Dec 13 | Dec 20 | Dec 25 | Jan 1 |
| 16°F97% of yrs | Nov 30 | Dec 8 | Dec 15 | Dec 22 | Dec 27 | Jan 1 | Jan 5 | Jan 12 | Jan 22 |
Freeze probabilities 1991–2020 at Rock Island Sp, TN, 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 38581 →Compare Rock Island with another place →
Weather by month in Rock Island
July is the warmest month at Rock Island Sp, TN, averaging 87°F by day and 68°F at night; January is the coldest at 48°F and 29°F. A freezing night is all but certain in every month from November to March (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 69% of years.
Warmth for growing adds up to 4,459 growing degree days a year (base 50°F), fewer than at 49% of the 144 Tennessee stations. 39% of them (1,744) have built up by the end of June, and July adds the most, 840.
| Month | High °F | Low °F | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|
| Jan | 48 | 29 | 100% | 21 | 28 |
| Feb | 53 | 32 | 100% | 16 | 45 |
| Mar | 62 | 39 | 99% | 8 | 127 |
| Apr | 70 | 47 | 69% | 1 | 285 |
| May | 78 | 56 | 0% | 0 | 530 |
| Jun | 84 | 64 | 0% | 0 | 729 |
| Jul | 87 | 68 | 0% | 0 | 840 |
| Aug | 86 | 67 | 0% | 0 | 814 |
| Sep | 80 | 61 | 0% | 0 | 613 |
| Oct | 71 | 48 | 55% | 1 | 309 |
| Nov | 61 | 38 | 98% | 10 | 99 |
| Dec | 52 | 32 | 100% | 17 | 40 |
Monthly normals 1991–2020 at Rock Island Sp, TN (880 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, Mc Minnville, TN, 10 miles southwest of Rock Island, has a last frost 1 day later (April 7), the same first-frost date, a season 4 days shorter.
When it snows in Rock Island, Tennessee
The first measurable snow (0.1 inch or more) in Rock Island usually arrives around January 7, and the last of the season around February 17. Those are the middle dates across the winters of 1991–2020 at Mc Minnville, TN, 9.7 miles away: half of years saw snow earlier, half later. Snow fell in 95% of those winters. The last 32°F night of spring typically comes 48 days after the last snow.
Planting calendar for 38581
| When | What to do |
|---|---|
| January 26 – February 9 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 9 – February 23 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 9 – March 23 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 6 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 7 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 16 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 30 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 38581 is 4 miles from Rock Island Sp, TN, which stands at 880 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 38581 in zone 7b, the band where the coldest night of the year averaged 5 to 10°F (-15.0 to -12.2°C) over 1991–2020; a zone describes winter lows, not frost dates.
Frost dates across Tennessee →
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.