Frost dates for 53151New Berlin, WI
The average last spring frost in New Berlin is May 1 and the average first fall frost is October 13, giving a typical growing season of about 162 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 1
- Average first fall frost
- Oct 13
- Growing season
- 162 days
Safer after May 18 (1-in-10 risk)
Possible by Sep 29 (1-in-10 risk)
Last frost typically in 179 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 29 · May 13 · May 29 | Sep 20 · Oct 2 · Oct 15 | 141 days | 100% |
| Frost / freeze (32°F) | Apr 18 · May 1 · May 18 | Sep 29 · Oct 13 · Oct 25 | 162 days | 100% |
| Hard freeze (28°F) | Apr 6 · Apr 19 · May 5 | Oct 8 · Oct 23 · Nov 6 | 185 days | 100% |
Planting calendar for New Berlin
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 31 – Jun 6 |
| Tomatoes | Transplant outdoors | May 17 – Jun 23 |
| Peppers | Start seeds indoors | Mar 31 – May 1 |
| Peppers | Transplant outdoors | May 31 – Jul 1 |
| Eggplant | Start seeds indoors | Apr 17 – May 16 |
| Eggplant | Transplant outdoors | May 31 – Jul 1 |
| Cucumbers | Sow outdoors | May 31 – Jul 3 |
| Summer squash | Sow outdoors | May 17 – Jul 1 |
| Winter squash & pumpkins | Sow outdoors | May 31 – Jul 1 |
| Snap beans | Sow outdoors | May 17 – Jul 26 |
| Sweet corn | Sow outdoors | May 17 – Jun 23 |
| Watermelon & cantaloupe | Sow outdoors | May 31 – Jul 1 |
| Okra | Sow outdoors | May 24 – Jun 16 |
| Peas | Sow outdoors (spring) | Mar 31 – May 16 |
| Potatoes | Plant outdoors (spring) | Mar 31 – May 31 |
| Onions | Start seeds indoors (spring) | Feb 17 – Mar 16 |
| Onions | Transplant outdoors (spring) | Apr 17 – May 16 |
| Broccoli | Start seeds indoors (spring) | Mar 13 – Apr 16 |
| Broccoli | Transplant outdoors (spring) | Apr 17 – May 16 |
| Broccoli | Start seeds indoors (fall) | Jun 13 – Jun 23 |
| Broccoli | Transplant outdoors (fall) | Jul 13 – Jul 24 |
| Cabbage | Start seeds indoors (spring) | Mar 3 – Mar 31 |
| Cabbage | Transplant outdoors (spring) | Mar 31 – May 1 |
| Cabbage | Start seeds indoors (fall) | Jun 3 – Jul 3 |
| Cabbage | Transplant outdoors (fall) | Jul 3 – Aug 3 |
| Leaf lettuce | Sow outdoors (spring) | Mar 31 – Jun 16 |
| Leaf lettuce | Sow outdoors (fall) | Jul 3 – Aug 19 |
| Spinach | Sow outdoors (spring) | Mar 24 – May 7 |
| Spinach | Sow outdoors (fall) | Jul 20 – Aug 24 |
| Radishes | Sow outdoors (spring) | Mar 31 – May 21 |
| Radishes | Sow outdoors (fall) | Jul 3 – Sep 3 |
| Kale | Sow outdoors (spring) | Apr 17 – May 7 |
| Kale | Sow outdoors (fall) | Jun 26 – Aug 3 |
| Carrots | Sow outdoors (spring) | May 1 – Jun 16 |
| Carrots | Sow outdoors (fall) | Jun 3 – Jul 19 |
| Garlic | Plant outdoors (fall) | Oct 3 – Nov 3 |
Where these dates come from
ZIP code 53151 is matched to the NOAA station Waukesha Wwtp, WI, 12.9 km away, at 789 ft elevation (97 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Waukesha Wwtp, WI (used) | 789 ft | May 1 | Oct 13 |
| Hales Corners/Whitnall Park/Bo, WI | 774 ft | May 3 | Oct 14 |
| West Allis, WI | 723 ft | Apr 26 | Oct 22 |
| Brookfield Wwtp, WI | 830 ft | Apr 30 | Oct 14 |
Frost dates near New Berlin
- Milwaukee, WI 53228 · last Apr 26, first Oct 18
- New Berlin, WI 53146 · last May 1, first Oct 13
- Hales Corners, WI 53130 · last May 3, first Oct 14
- Elm Grove, WI 53122 · last Apr 26, first Oct 18
- Brookfield, WI 53008 · last Apr 26, first Oct 18
- Muskego, WI 53150 · last May 1, first Oct 13
- Greendale, WI 53129 · last Apr 19, first Oct 29
- Waukesha, WI 53186 · last May 1, first Oct 13
Frequently asked questions
- When is the last frost in New Berlin, WI?
- For ZIP code 53151, the average last spring frost (32°F) is May 1, based on NOAA 1991-2020 climate normals for the Waukesha Wwtp, WI weather station. There is a 1-in-10 chance of a frost after May 18.
- When is the first frost in New Berlin, WI?
- The average first fall frost (32°F) is October 13. There is a 1-in-10 chance of frost by September 29, so tender plants are at risk from that point on.
- How long is the growing season in 53151?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 162 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.