Frost dates for 37166Smithville, TN
The average last spring frost in Smithville is April 18 and the average first fall frost is October 22, giving a typical growing season of about 187 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 18
- Average first fall frost
- Oct 22
- Growing season
- 187 days
Safer after May 2 (1-in-10 risk)
Possible by Oct 10 (1-in-10 risk)
Last frost typically in 166 days
Frost risk by date
NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.
| Temperature | Last spring: 90% / 50% / 10% chance | First fall: 10% / 50% / 90% chance | Growing season (50%) | Years with at least one |
|---|---|---|---|---|
| Light frost (36°F) | Apr 16 · Apr 30 · May 14 | Oct 1 · Oct 13 · Oct 26 | 167 days | 100% |
| Frost / freeze (32°F) | Apr 2 · Apr 18 · May 2 | Oct 10 · Oct 22 · Nov 4 | 187 days | 100% |
| Hard freeze (28°F) | Mar 18 · Apr 4 · Apr 20 | Oct 19 · Nov 1 · Nov 13 | 209 days | 100% |
Planting calendar for Smithville
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | Mar 18 – May 24 |
| Tomatoes | Transplant outdoors | May 4 – Jul 2 |
| Peppers | Start seeds indoors | Mar 18 – Apr 18 |
| Peppers | Transplant outdoors | May 18 – Jun 18 |
| Eggplant | Start seeds indoors | Apr 4 – May 3 |
| Eggplant | Transplant outdoors | May 18 – Jun 18 |
| Cucumbers | Sow outdoors | May 18 – Jul 12 |
| Summer squash | Sow outdoors | May 4 – Jun 18 |
| Winter squash & pumpkins | Sow outdoors | May 18 – Jun 18 |
| Snap beans | Sow outdoors | May 4 – Aug 4 |
| Sweet corn | Sow outdoors | May 4 – Jul 2 |
| Watermelon & cantaloupe | Sow outdoors | May 18 – Jun 18 |
| Okra | Sow outdoors | May 11 – Jun 3 |
| Peas | Sow outdoors (spring) | Mar 18 – May 3 |
| Potatoes | Plant outdoors (spring) | Mar 18 – May 18 |
| Onions | Start seeds indoors (spring) | Feb 4 – Mar 3 |
| Onions | Transplant outdoors (spring) | Apr 4 – May 3 |
| Broccoli | Start seeds indoors (spring) | Feb 28 – Apr 3 |
| Broccoli | Transplant outdoors (spring) | Apr 4 – May 3 |
| Broccoli | Start seeds indoors (fall) | Jun 22 – Jul 2 |
| Broccoli | Transplant outdoors (fall) | Jul 22 – Aug 2 |
| Cabbage | Start seeds indoors (spring) | Feb 18 – Mar 18 |
| Cabbage | Transplant outdoors (spring) | Mar 18 – Apr 18 |
| Cabbage | Start seeds indoors (fall) | Jun 12 – Jul 12 |
| Cabbage | Transplant outdoors (fall) | Jul 12 – Aug 12 |
| Leaf lettuce | Sow outdoors (spring) | Mar 18 – Jun 3 |
| Leaf lettuce | Sow outdoors (fall) | Jul 12 – Aug 28 |
| Spinach | Sow outdoors (spring) | Mar 11 – Apr 24 |
| Spinach | Sow outdoors (fall) | Jul 29 – Sep 2 |
| Radishes | Sow outdoors (spring) | Mar 18 – May 8 |
| Radishes | Sow outdoors (fall) | Jul 12 – Sep 12 |
| Kale | Sow outdoors (spring) | Apr 4 – Apr 24 |
| Kale | Sow outdoors (fall) | Jul 5 – Aug 12 |
| Carrots | Sow outdoors (spring) | Apr 18 – Jun 3 |
| Carrots | Sow outdoors (fall) | Jun 12 – Jul 28 |
| Garlic | Plant outdoors (fall) | Oct 12 – Nov 12 |
Where these dates come from
ZIP code 37166 is matched to the NOAA station Smithville 2 Se, TN, 1.9 km away, at 890 ft elevation (147 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Smithville 2 Se, TN (used) | 890 ft | Apr 18 | Oct 22 |
| Lancaster Edgar Evins Marina, TN | 630 ft | Apr 3 | Nov 4 |
| Rock Island Sp, TN | 880 ft | Apr 6 | Oct 30 |
| Woodbury 1 Wnw, TN | 750 ft | Apr 17 | Oct 21 |
Frost dates near Smithville
- Dowelltown, TN 37059 · last Apr 18, first Oct 22
- Liberty, TN 37095 · last Apr 3, first Nov 4
- Walling, TN 38587 · last Apr 15, first Oct 23
- Lancaster, TN 38569 · last Apr 3, first Nov 4
- Silver Point, TN 38582 · last Apr 14, first Oct 25
- Rock Island, TN 38581 · last Apr 7, first Oct 30
- Hickman, TN 38567 · last Apr 3, first Nov 4
- Campaign, TN 38550 · last Apr 7, first Oct 30
Frequently asked questions
- When is the last frost in Smithville, TN?
- For ZIP code 37166, the average last spring frost (32°F) is April 18, based on NOAA 1991-2020 climate normals for the Smithville 2 Se, TN weather station. There is a 1-in-10 chance of a frost after May 2.
- When is the first frost in Smithville, TN?
- The average first fall frost (32°F) is October 22. There is a 1-in-10 chance of frost by October 10, so tender plants are at risk from that point on.
- How long is the growing season in 37166?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 187 days long.
- Are these frost dates a forecast?
- No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.