Frost dates for 53518Blue River, WI
The average last spring frost in Blue River is May 3 and the average first fall frost is October 7, giving a typical growing season of about 155 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 3
- Average first fall frost
- Oct 7
- Growing season
- 155 days
Safer after May 18 (1-in-10 risk)
Possible by Sep 25 (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) | Apr 30 · May 14 · May 28 | Sep 17 · Sep 29 · Oct 11 | 136 days | 100% |
| Frost / freeze (32°F) | Apr 19 · May 3 · May 18 | Sep 25 · Oct 7 · Oct 20 | 155 days | 100% |
| Hard freeze (28°F) | Apr 7 · Apr 22 · May 8 | Oct 4 · Oct 17 · Oct 31 | 177 days | 100% |
Planting calendar for Blue River
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 17 |
| 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 27 |
| Summer squash | Sow outdoors | May 19 – Jul 3 |
| Winter squash & pumpkins | Sow outdoors | Jun 2 – Jul 3 |
| Snap beans | Sow outdoors | May 19 – Jul 20 |
| Sweet corn | Sow outdoors | May 19 – Jun 17 |
| 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 7 – Jun 17 |
| Broccoli | Transplant outdoors (fall) | Jul 7 – Jul 18 |
| Cabbage | Start seeds indoors (spring) | Mar 5 – Apr 2 |
| Cabbage | Transplant outdoors (spring) | Apr 2 – May 3 |
| Cabbage | Start seeds indoors (fall) | May 28 – Jun 27 |
| Cabbage | Transplant outdoors (fall) | Jun 27 – Jul 28 |
| Leaf lettuce | Sow outdoors (spring) | Apr 2 – Jun 18 |
| Leaf lettuce | Sow outdoors (fall) | Jun 27 – Aug 13 |
| Spinach | Sow outdoors (spring) | Mar 26 – May 9 |
| Spinach | Sow outdoors (fall) | Jul 14 – Aug 18 |
| Radishes | Sow outdoors (spring) | Apr 2 – May 23 |
| Radishes | Sow outdoors (fall) | Jun 27 – Aug 28 |
| Kale | Sow outdoors (spring) | Apr 19 – May 9 |
| Kale | Sow outdoors (fall) | Jun 20 – Jul 28 |
| Carrots | Sow outdoors (spring) | May 3 – Jun 18 |
| Carrots | Sow outdoors (fall) | May 28 – Jul 13 |
| Garlic | Plant outdoors (fall) | Sep 27 – Oct 28 |
Where these dates come from
ZIP code 53518 is matched to the NOAA station Boscobel Ap, WI, 11.6 km away, at 672 ft elevation (345 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Boscobel Ap, WI (used) | 672 ft | May 3 | Oct 7 |
| Richland Ctr, WI | 728 ft | May 5 | Oct 6 |
| Gays Mills, WI | 689 ft | May 3 | Oct 7 |
| Steuben 4 Se, WI | 1,015 ft | Apr 22 | Oct 20 |
Frost dates near Blue River
- Muscoda, WI 53573 · last May 5, first Oct 6
- Boscobel, WI 53805 · last May 3, first Oct 7
- Richland Center, WI 53581 · last May 5, first Oct 6
- Soldiers Grove, WI 54655 · last May 3, first Oct 7
- Steuben, WI 54657 · last Apr 22, first Oct 20
- Gays Mills, WI 54631 · last May 3, first Oct 7
- Gotham, WI 53540 · last Apr 30, first Oct 9
- Sextonville, WI 53584 · last May 5, first Oct 6
Frequently asked questions
- When is the last frost in Blue River, WI?
- For ZIP code 53518, the average last spring frost (32°F) is May 3, based on NOAA 1991-2020 climate normals for the Boscobel Ap, WI weather station. There is a 1-in-10 chance of a frost after May 18.
- When is the first frost in Blue River, WI?
- The average first fall frost (32°F) is October 7. There is a 1-in-10 chance of frost by September 25, so tender plants are at risk from that point on.
- How long is the growing season in 53518?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 155 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.