Frost dates for 50046Cambridge, IA
The average last spring frost in Cambridge is April 26 and the average first fall frost is October 12, giving a typical growing season of about 168 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 26
- Average first fall frost
- Oct 12
- Growing season
- 168 days
Safer after May 8 (1-in-10 risk)
Possible by Sep 26 (1-in-10 risk)
Last frost typically in 175 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 21 · May 5 · May 17 | Sep 18 · Oct 1 · Oct 14 | 148 days | 100% |
| Frost / freeze (32°F) | Apr 11 · Apr 26 · May 8 | Sep 26 · Oct 12 · Oct 25 | 168 days | 100% |
| Hard freeze (28°F) | Apr 2 · Apr 15 · Apr 30 | Oct 7 · Oct 22 · Nov 3 | 189 days | 100% |
Planting calendar for Cambridge
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 26 – Jun 1 |
| Tomatoes | Transplant outdoors | May 12 – Jun 22 |
| Peppers | Start seeds indoors | Mar 26 – Apr 26 |
| Peppers | Transplant outdoors | May 26 – Jun 26 |
| Eggplant | Start seeds indoors | Apr 12 – May 11 |
| Eggplant | Transplant outdoors | May 26 – Jun 26 |
| Cucumbers | Sow outdoors | May 26 – Jul 2 |
| Summer squash | Sow outdoors | May 12 – Jun 26 |
| Winter squash & pumpkins | Sow outdoors | May 26 – Jun 26 |
| Snap beans | Sow outdoors | May 12 – Jul 25 |
| Sweet corn | Sow outdoors | May 12 – Jun 22 |
| Watermelon & cantaloupe | Sow outdoors | May 26 – Jun 26 |
| Okra | Sow outdoors | May 19 – Jun 11 |
| Peas | Sow outdoors (spring) | Mar 26 – May 11 |
| Potatoes | Plant outdoors (spring) | Mar 26 – May 26 |
| Onions | Start seeds indoors (spring) | Feb 12 – Mar 11 |
| Onions | Transplant outdoors (spring) | Apr 12 – May 11 |
| Broccoli | Start seeds indoors (spring) | Mar 8 – Apr 11 |
| Broccoli | Transplant outdoors (spring) | Apr 12 – May 11 |
| Broccoli | Start seeds indoors (fall) | Jun 12 – Jun 22 |
| Broccoli | Transplant outdoors (fall) | Jul 12 – Jul 23 |
| Cabbage | Start seeds indoors (spring) | Feb 26 – Mar 26 |
| Cabbage | Transplant outdoors (spring) | Mar 26 – Apr 26 |
| Cabbage | Start seeds indoors (fall) | Jun 2 – Jul 2 |
| Cabbage | Transplant outdoors (fall) | Jul 2 – Aug 2 |
| Leaf lettuce | Sow outdoors (spring) | Mar 26 – Jun 11 |
| Leaf lettuce | Sow outdoors (fall) | Jul 2 – Aug 18 |
| Spinach | Sow outdoors (spring) | Mar 19 – May 2 |
| Spinach | Sow outdoors (fall) | Jul 19 – Aug 23 |
| Radishes | Sow outdoors (spring) | Mar 26 – May 16 |
| Radishes | Sow outdoors (fall) | Jul 2 – Sep 2 |
| Kale | Sow outdoors (spring) | Apr 12 – May 2 |
| Kale | Sow outdoors (fall) | Jun 25 – Aug 2 |
| Carrots | Sow outdoors (spring) | Apr 26 – Jun 11 |
| Carrots | Sow outdoors (fall) | Jun 2 – Jul 18 |
| Garlic | Plant outdoors (fall) | Oct 2 – Nov 2 |
Where these dates come from
ZIP code 50046 is matched to the NOAA station Ames 5 Se, IA, 6.2 km away, at 870 ft elevation (20 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Ames 5 Se, IA (used) | 870 ft | Apr 26 | Oct 12 |
| Ames Muni Ap, IA | 930 ft | Apr 26 | Oct 8 |
| Ankeny, IA | 975 ft | Apr 23 | Oct 15 |
| Colo, IA | 1,000 ft | Apr 24 | Oct 12 |
Frost dates near Cambridge
- Huxley, IA 50124 · last Apr 26, first Oct 12
- Maxwell, IA 50161 · last Apr 26, first Oct 12
- Alleman, IA 50007 · last Apr 23, first Oct 15
- Kelley, IA 50134 · last Apr 26, first Oct 8
- Elkhart, IA 50073 · last Apr 23, first Oct 15
- Slater, IA 50244 · last Apr 26, first Oct 8
- Sheldahl, IA 50243 · last Apr 19, first Oct 18
- Nevada, IA 50201 · last Apr 24, first Oct 12
Frequently asked questions
- When is the last frost in Cambridge, IA?
- For ZIP code 50046, the average last spring frost (32°F) is April 26, based on NOAA 1991-2020 climate normals for the Ames 5 Se, IA weather station. There is a 1-in-10 chance of a frost after May 8.
- When is the first frost in Cambridge, IA?
- The average first fall frost (32°F) is October 12. There is a 1-in-10 chance of frost by September 26, so tender plants are at risk from that point on.
- How long is the growing season in 50046?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 168 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.