USDA Hardiness Zone 7b
Frost Dates for 37046 — College Grove, Tennessee
NOAA 1991–2020 normals from Thompson Stn, TN (775 ft), 12 miles west.
Updated
In College Grove, the last spring frost (32°F) is around April 3 in half of years and has passed by April 22 in nine years out of ten. The first fall frost comes around November 1, as early as October 20 one year in ten, leaving a typical freeze-free season of 211 days (NOAA, Thompson Stn, TN).
- Last spring frost
- April 3
- First fall frost
- November 1
- Growing season
- 211 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 6
- Last snow
- February 27
- Winters with snow
- 100%
- Snow per year
- 3.5"
median, 1991–2020
median, 1991–2020
18 of 18 observed
NOAA normal
Frost risk by date in College Grove
Half of springs at Thompson Stn, TN see their last 32°F night by April 3; only one in ten is past it by March 17, and one in ten still has one after April 22. Planting tender crops after April 10 leaves a 30% risk of a frost on them, after April 15 20%, and after April 22 10%. The 19 days between the even-odds date and the one-in-ten date is wider than at 84% of the 144 Tennessee stations behind this site's ZIP pages.
In fall the first 32°F night comes by November 1 in half of years, as early as October 20 one year in ten, and holds off past November 15 one year in ten. A hard freeze of 28°F follows 10 days later, around November 11; in spring the one-in-ten date for 28°F is April 11, 11 days before the 32°F one. The freeze-free season lasts 211 days in a typical year, longer than at 74% of the 144 Tennessee stations; it reaches 233 days one year in ten and falls short of 190 one year in ten. On average 80 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 14 days longer, to about April 17, and return around October 23. Severe cold of 16°F or below comes in 98% of winters, usually between December 24 and February 11.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 1 | Apr 6 | Apr 10 | Apr 14 | Apr 17 | Apr 20 | Apr 24 | Apr 28 | May 2 |
| 32°F | Mar 17 | Mar 22 | Mar 28 | Mar 31 | Apr 3 | Apr 6 | Apr 10 | Apr 15 | Apr 22 |
| 28°F | Mar 2 | Mar 8 | Mar 14 | Mar 18 | Mar 23 | Mar 26 | Mar 31 | Apr 3 | Apr 11 |
| 24°F | Feb 17 | Feb 25 | Feb 28 | Mar 4 | Mar 8 | Mar 13 | Mar 17 | Mar 23 | Apr 1 |
| 20°F | Feb 3 | Feb 11 | Feb 16 | Feb 21 | Feb 25 | Mar 1 | Mar 4 | Mar 10 | Mar 16 |
| 16°F98% of yrs | Jan 18 | Jan 26 | Jan 31 | Feb 5 | Feb 11 | Feb 16 | Feb 21 | Feb 26 | Mar 5 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 11 | Oct 15 | Oct 18 | Oct 20 | Oct 23 | Oct 25 | Oct 28 | Oct 31 | Nov 4 |
| 32°F | Oct 20 | Oct 24 | Oct 27 | Oct 31 | Nov 1 | Nov 4 | Nov 7 | Nov 10 | Nov 15 |
| 28°F | Oct 30 | Nov 2 | Nov 5 | Nov 8 | Nov 11 | Nov 15 | Nov 18 | Nov 23 | Nov 30 |
| 24°F | Nov 6 | Nov 12 | Nov 16 | Nov 20 | Nov 24 | Nov 28 | Dec 1 | Dec 6 | Dec 14 |
| 20°F | Nov 15 | Nov 23 | Nov 28 | Dec 2 | Dec 6 | Dec 10 | Dec 15 | Dec 22 | Dec 29 |
| 16°F98% of yrs | Dec 1 | Dec 6 | Dec 11 | Dec 18 | Dec 24 | Dec 29 | Jan 2 | Jan 8 | Jan 18 |
Freeze probabilities 1991–2020 at Thompson Stn, 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 37046 →Compare College Grove with another place →
Weather by month in College Grove
July is the warmest month at Thompson Stn, TN, averaging 89°F by day and 69°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 59% of years.
Warmth for growing adds up to 4,827 growing degree days a year (base 50°F), more than at 85% of the 144 Tennessee stations. 38% of them (1,845) have built up by the end of June, and July adds the most, 911. Precipitation totals 55.9 inches a year, most in December (5.8") and least in August (3.6"); May to September bring 39% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 48 | 29 | 4.6 | 100% | 21 | 25 |
| Feb | 51 | 32 | 5.2 | 100% | 17 | 38 |
| Mar | 61 | 39 | 5.0 | 98% | 9 | 126 |
| Apr | 71 | 47 | 5.3 | 59% | 2 | 301 |
| May | 79 | 57 | 5.1 | 1% | 0 | 565 |
| Jun | 87 | 66 | 4.6 | 0% | 0 | 790 |
| Jul | 89 | 69 | 4.6 | 0% | 0 | 911 |
| Aug | 89 | 69 | 3.6 | 0% | 0 | 896 |
| Sep | 84 | 62 | 4.1 | 0% | 0 | 684 |
| Oct | 73 | 49 | 3.8 | 44% | 2 | 351 |
| Nov | 61 | 38 | 4.2 | 99% | 10 | 103 |
| Dec | 51 | 32 | 5.8 | 100% | 18 | 38 |
Monthly normals 1991–2020 at Thompson Stn, TN (775 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, Christiana 5W, TN, 14 miles east of College Grove, has a last frost 11 days later (April 14), a first frost 7 days earlier (October 25), a season 19 days shorter.
When it snows in College Grove, Tennessee
The first measurable snow (0.1 inch or more) in College Grove usually arrives around January 6, and the last of the season around February 27. Those are the middle dates across the winters of 1991–2020 at Thompson Stn, TN, 11.8 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 35 days after the last snow.
Planting calendar for 37046
| When | What to do |
|---|---|
| January 23 – February 6 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 6 – February 20 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 6 – March 20 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 3 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 9 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 18 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| November 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 37046 is 12 miles from Thompson Stn, TN, which stands at 775 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station; its figures are presented in full for 37174 (Spring Hill). The 2023 USDA Plant Hardiness Zone Map lists ZIP 37046 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.