Frost dates for 57061Sinai, SD
The average last spring frost in Sinai is May 3 and the average first fall frost is October 2, giving a typical growing season of about 151 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 3
- Average first fall frost
- Oct 2
- Growing season
- 151 days
Safer after May 15 (1-in-10 risk)
Possible by Sep 19 (1-in-10 risk)
Last frost typically in 181 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) | May 1 · May 13 · May 27 | Sep 12 · Sep 25 · Oct 6 | 134 days | 100% |
| Frost / freeze (32°F) | Apr 21 · May 3 · May 15 | Sep 19 · Oct 2 · Oct 16 | 151 days | 100% |
| Hard freeze (28°F) | Apr 10 · Apr 25 · May 7 | Sep 27 · Oct 10 · Oct 27 | 170 days | 100% |
Planting calendar for Sinai
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 | Apr 2 – Jun 8 |
| Tomatoes | Transplant outdoors | May 19 – Jun 12 |
| Peppers | Start seeds indoors | Apr 2 – May 3 |
| Peppers | Transplant outdoors | Jun 2 – Jul 3 |
| Eggplant | Start seeds indoors | Apr 19 – May 18 |
| Eggplant | Transplant outdoors | Jun 2 – Jul 3 |
| Cucumbers | Sow outdoors | Jun 2 – Jun 22 |
| Summer squash | Sow outdoors | May 19 – Jul 3 |
| Winter squash & pumpkins | Sow outdoors | Jun 2 – Jul 3 |
| Snap beans | Sow outdoors | May 19 – Jul 15 |
| Sweet corn | Sow outdoors | May 19 – Jun 12 |
| Watermelon & cantaloupe | Sow outdoors | Jun 2 – Jul 3 |
| Okra | Sow outdoors | May 26 – Jun 18 |
| Peas | Sow outdoors (spring) | Apr 2 – May 18 |
| Potatoes | Plant outdoors (spring) | Apr 2 – Jun 2 |
| Onions | Start seeds indoors (spring) | Feb 19 – Mar 18 |
| Onions | Transplant outdoors (spring) | Apr 19 – May 18 |
| Broccoli | Start seeds indoors (spring) | Mar 15 – Apr 18 |
| Broccoli | Transplant outdoors (spring) | Apr 19 – May 18 |
| Broccoli | Start seeds indoors (fall) | Jun 2 – Jun 12 |
| Broccoli | Transplant outdoors (fall) | Jul 2 – Jul 13 |
| Cabbage | Start seeds indoors (spring) | Mar 5 – Apr 2 |
| Cabbage | Transplant outdoors (spring) | Apr 2 – May 3 |
| Cabbage | Start seeds indoors (fall) | May 23 – Jun 22 |
| Cabbage | Transplant outdoors (fall) | Jun 22 – Jul 23 |
| Leaf lettuce | Sow outdoors (spring) | Apr 2 – Jun 18 |
| Leaf lettuce | Sow outdoors (fall) | Jun 22 – Aug 8 |
| Spinach | Sow outdoors (spring) | Mar 26 – May 9 |
| Spinach | Sow outdoors (fall) | Jul 9 – Aug 13 |
| Radishes | Sow outdoors (spring) | Apr 2 – May 23 |
| Radishes | Sow outdoors (fall) | Jun 22 – Aug 23 |
| Kale | Sow outdoors (spring) | Apr 19 – May 9 |
| Kale | Sow outdoors (fall) | Jun 15 – Jul 23 |
| Carrots | Sow outdoors (spring) | May 3 – Jun 18 |
| Carrots | Sow outdoors (fall) | May 23 – Jul 8 |
| Garlic | Plant outdoors (fall) | Sep 22 – Oct 23 |
Where these dates come from
ZIP code 57061 is matched to the NOAA station Arlington 1 W, SD, 16.7 km away, at 1,824 ft elevation (39 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Arlington 1 W, SD (used) | 1,824 ft | May 3 | Oct 2 |
| Brookings 2 Ne, SD | 1,639 ft | May 6 | Oct 1 |
| Wentworth 2.5 Wnw, SD | 1,722 ft | May 2 | Oct 5 |
| Madison 2Se, SD | 1,643 ft | May 5 | Sep 30 |
Frost dates near Sinai
- Nunda, SD 57050 · last May 2, first Oct 5
- Volga, SD 57071 · last May 6, first Oct 1
- Arlington, SD 57212 · last May 3, first Oct 2
- Oldham, SD 57051 · last May 3, first Oct 2
- Ramona, SD 57054 · last May 5, first Sep 30
- Rutland, SD 57057 · last May 2, first Oct 5
- Brookings, SD 57006 · last May 6, first Oct 1
- Bruce, SD 57220 · last May 6, first Oct 1
Frequently asked questions
- When is the last frost in Sinai, SD?
- For ZIP code 57061, the average last spring frost (32°F) is May 3, based on NOAA 1991-2020 climate normals for the Arlington 1 W, SD weather station. There is a 1-in-10 chance of a frost after May 15.
- When is the first frost in Sinai, SD?
- The average first fall frost (32°F) is October 2. There is a 1-in-10 chance of frost by September 19, so tender plants are at risk from that point on.
- How long is the growing season in 57061?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 151 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.