Frost dates for 37748Harriman, TN
The average last spring frost in Harriman is April 3 and the average first fall frost is November 4, giving a typical growing season of about 215 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 3
- Average first fall frost
- Nov 4
- Growing season
- 215 days
Safer after Apr 20 (1-in-10 risk)
Possible by Oct 23 (1-in-10 risk)
First frost typically in 1 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) | Mar 31 · Apr 17 · May 4 | Oct 13 · Oct 26 · Nov 6 | 192 days | 100% |
| Frost / freeze (32°F) | Mar 16 · Apr 3 · Apr 20 | Oct 23 · Nov 4 · Nov 18 | 215 days | 100% |
| Hard freeze (28°F) | Mar 2 · Mar 20 · Apr 5 | Nov 3 · Nov 15 · Dec 3 | 240 days | 100% |
Planting calendar for Harriman
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 3 – May 9 |
| Tomatoes | Transplant outdoors | Apr 19 – Jul 15 |
| Peppers | Start seeds indoors | Mar 3 – Apr 3 |
| Peppers | Transplant outdoors | May 3 – Jun 3 |
| Eggplant | Start seeds indoors | Mar 20 – Apr 18 |
| Eggplant | Transplant outdoors | May 3 – Jun 3 |
| Cucumbers | Sow outdoors | May 3 – Jul 25 |
| Summer squash | Sow outdoors | Apr 19 – Jun 3 |
| Winter squash & pumpkins | Sow outdoors | May 3 – Jun 3 |
| Snap beans | Sow outdoors | Apr 19 – Aug 17 |
| Sweet corn | Sow outdoors | Apr 19 – Jul 15 |
| Watermelon & cantaloupe | Sow outdoors | May 3 – Jun 3 |
| Okra | Sow outdoors | Apr 26 – May 19 |
| Peas | Sow outdoors (spring) | Mar 3 – Apr 18 |
| Potatoes | Plant outdoors (spring) | Mar 3 – May 3 |
| Onions | Start seeds indoors (spring) | Jan 20 – Feb 16 |
| Onions | Transplant outdoors (spring) | Mar 20 – Apr 18 |
| Broccoli | Start seeds indoors (spring) | Feb 13 – Mar 19 |
| Broccoli | Transplant outdoors (spring) | Mar 20 – Apr 18 |
| Broccoli | Start seeds indoors (fall) | Jul 5 – Jul 15 |
| Broccoli | Transplant outdoors (fall) | Aug 4 – Aug 15 |
| Cabbage | Start seeds indoors (spring) | Feb 3 – Mar 3 |
| Cabbage | Transplant outdoors (spring) | Mar 3 – Apr 3 |
| Cabbage | Start seeds indoors (fall) | Jun 25 – Jul 25 |
| Cabbage | Transplant outdoors (fall) | Jul 25 – Aug 25 |
| Leaf lettuce | Sow outdoors (spring) | Mar 3 – May 19 |
| Leaf lettuce | Sow outdoors (fall) | Jul 25 – Sep 10 |
| Spinach | Sow outdoors (spring) | Feb 24 – Apr 9 |
| Spinach | Sow outdoors (fall) | Aug 11 – Sep 15 |
| Radishes | Sow outdoors (spring) | Mar 3 – Apr 23 |
| Radishes | Sow outdoors (fall) | Jul 25 – Sep 25 |
| Kale | Sow outdoors (spring) | Mar 20 – Apr 9 |
| Kale | Sow outdoors (fall) | Jul 18 – Aug 25 |
| Carrots | Sow outdoors (spring) | Apr 3 – May 19 |
| Carrots | Sow outdoors (fall) | Jun 25 – Aug 10 |
| Garlic | Plant outdoors (fall) | Oct 25 – Nov 25 |
Where these dates come from
ZIP code 37748 is matched to the NOAA station Kingston, TN, 8.7 km away, at 814 ft elevation (154 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Kingston, TN (used) | 814 ft | Apr 3 | Nov 4 |
| Rockwood 2, TN | 767 ft | Apr 8 | Oct 31 |
| Oak Ridge Atdd, TN | 905 ft | Apr 5 | Nov 1 |
| Oak Ridge Asos, TN | 910 ft | Mar 31 | Nov 4 |
Frost dates near Harriman
- Kingston, TN 37763 · last Apr 3, first Nov 4
- Oakdale, TN 37829 · last Apr 3, first Nov 4
- Coalfield, TN 37719 · last Apr 5, first Nov 1
- Rockwood, TN 37854 · last Apr 8, first Oct 31
- Oliver Springs, TN 37840 · last Apr 5, first Nov 1
- Wartburg, TN 37887 · last Apr 21, first Oct 17
- Petros, TN 37845 · last Apr 21, first Oct 17
- Oak Ridge, TN 37830 · last Apr 5, first Nov 1
Frequently asked questions
- When is the last frost in Harriman, TN?
- For ZIP code 37748, the average last spring frost (32°F) is April 3, based on NOAA 1991-2020 climate normals for the Kingston, TN weather station. There is a 1-in-10 chance of a frost after April 20.
- When is the first frost in Harriman, TN?
- The average first fall frost (32°F) is November 4. There is a 1-in-10 chance of frost by October 23, so tender plants are at risk from that point on.
- How long is the growing season in 37748?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 215 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.