Frost dates for 37930Knoxville, TN
The average last spring frost in Knoxville is April 11 and the average first fall frost is October 28, giving a typical growing season of about 198 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 11
- Average first fall frost
- Oct 28
- Growing season
- 198 days
Safer after Apr 29 (1-in-10 risk)
Possible by Oct 13 (1-in-10 risk)
Last frost typically in 159 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 9 · Apr 24 · May 10 | Oct 7 · Oct 19 · Nov 1 | 178 days | 100% |
| Frost / freeze (32°F) | Mar 26 · Apr 11 · Apr 29 | Oct 13 · Oct 28 · Nov 9 | 198 days | 100% |
| Hard freeze (28°F) | Mar 13 · Mar 31 · Apr 16 | Oct 24 · Nov 6 · Nov 20 | 221 days | 100% |
Planting calendar for Knoxville
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 11 – May 17 |
| Tomatoes | Transplant outdoors | Apr 27 – Jul 8 |
| Peppers | Start seeds indoors | Mar 11 – Apr 11 |
| Peppers | Transplant outdoors | May 11 – Jun 11 |
| Eggplant | Start seeds indoors | Mar 28 – Apr 26 |
| Eggplant | Transplant outdoors | May 11 – Jun 11 |
| Cucumbers | Sow outdoors | May 11 – Jul 18 |
| Summer squash | Sow outdoors | Apr 27 – Jun 11 |
| Winter squash & pumpkins | Sow outdoors | May 11 – Jun 11 |
| Snap beans | Sow outdoors | Apr 27 – Aug 10 |
| Sweet corn | Sow outdoors | Apr 27 – Jul 8 |
| Watermelon & cantaloupe | Sow outdoors | May 11 – Jun 11 |
| Okra | Sow outdoors | May 4 – May 27 |
| Peas | Sow outdoors (spring) | Mar 11 – Apr 26 |
| Potatoes | Plant outdoors (spring) | Mar 11 – May 11 |
| Onions | Start seeds indoors (spring) | Jan 28 – Feb 24 |
| Onions | Transplant outdoors (spring) | Mar 28 – Apr 26 |
| Broccoli | Start seeds indoors (spring) | Feb 21 – Mar 27 |
| Broccoli | Transplant outdoors (spring) | Mar 28 – Apr 26 |
| Broccoli | Start seeds indoors (fall) | Jun 28 – Jul 8 |
| Broccoli | Transplant outdoors (fall) | Jul 28 – Aug 8 |
| Cabbage | Start seeds indoors (spring) | Feb 11 – Mar 11 |
| Cabbage | Transplant outdoors (spring) | Mar 11 – Apr 11 |
| Cabbage | Start seeds indoors (fall) | Jun 18 – Jul 18 |
| Cabbage | Transplant outdoors (fall) | Jul 18 – Aug 18 |
| Leaf lettuce | Sow outdoors (spring) | Mar 11 – May 27 |
| Leaf lettuce | Sow outdoors (fall) | Jul 18 – Sep 3 |
| Spinach | Sow outdoors (spring) | Mar 4 – Apr 17 |
| Spinach | Sow outdoors (fall) | Aug 4 – Sep 8 |
| Radishes | Sow outdoors (spring) | Mar 11 – May 1 |
| Radishes | Sow outdoors (fall) | Jul 18 – Sep 18 |
| Kale | Sow outdoors (spring) | Mar 28 – Apr 17 |
| Kale | Sow outdoors (fall) | Jul 11 – Aug 18 |
| Carrots | Sow outdoors (spring) | Apr 11 – May 27 |
| Carrots | Sow outdoors (fall) | Jun 18 – Aug 3 |
| Garlic | Plant outdoors (fall) | Oct 18 – Nov 18 |
Where these dates come from
ZIP code 37930 is matched to the NOAA station Knoxville Exp Stn, TN, 0.6 km away, at 830 ft elevation (30 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Knoxville Exp Stn, TN (used) | 830 ft | Apr 11 | Oct 28 |
| Knoxville Mcghee Tyson Ap, TN | 962 ft | Apr 1 | Nov 2 |
| Oak Ridge Atdd, TN | 905 ft | Apr 5 | Nov 1 |
| Oak Ridge Asos, TN | 910 ft | Mar 31 | Nov 4 |
Frost dates near Knoxville
- Knoxville, TN 37920 · last Apr 11, first Oct 28
- Rockford, TN 37853 · last Apr 1, first Nov 2
- Louisville, TN 37777 · last Apr 1, first Nov 2
- Maryville, TN 37804 · last Apr 11, first Oct 28
- Alcoa, TN 37701 · last Apr 1, first Nov 2
- Powell, TN 37849 · last Apr 22, first Oct 25
- Seymour, TN 37865 · last Apr 6, first Oct 29
- Walland, TN 37886 · last Apr 1, first Nov 2
Frequently asked questions
- When is the last frost in Knoxville, TN?
- For ZIP code 37930, the average last spring frost (32°F) is April 11, based on NOAA 1991-2020 climate normals for the Knoxville Exp Stn, TN weather station. There is a 1-in-10 chance of a frost after April 29.
- When is the first frost in Knoxville, TN?
- The average first fall frost (32°F) is October 28. There is a 1-in-10 chance of frost by October 13, so tender plants are at risk from that point on.
- How long is the growing season in 37930?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 198 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.