Frost dates for 52099Dubuque, IA
The average last spring frost in Dubuque is April 19 and the average first fall frost is October 21, giving a typical growing season of about 184 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 19
- Average first fall frost
- Oct 21
- Growing season
- 184 days
Safer after May 4 (1-in-10 risk)
Possible by Oct 7 (1-in-10 risk)
Last frost typically in 174 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 16 · May 1 · May 14 | Sep 29 · Oct 12 · Oct 24 | 163 days | 100% |
| Frost / freeze (32°F) | Apr 4 · Apr 19 · May 4 | Oct 7 · Oct 21 · Nov 2 | 184 days | 100% |
| Hard freeze (28°F) | Mar 25 · Apr 7 · Apr 22 | Oct 19 · Nov 1 · Nov 14 | 205 days | 100% |
Planting calendar for Dubuque
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 19 – May 25 |
| Tomatoes | Transplant outdoors | May 5 – Jul 1 |
| Peppers | Start seeds indoors | Mar 19 – Apr 19 |
| Peppers | Transplant outdoors | May 19 – Jun 19 |
| Eggplant | Start seeds indoors | Apr 5 – May 4 |
| Eggplant | Transplant outdoors | May 19 – Jun 19 |
| Cucumbers | Sow outdoors | May 19 – Jul 11 |
| Summer squash | Sow outdoors | May 5 – Jun 19 |
| Winter squash & pumpkins | Sow outdoors | May 19 – Jun 19 |
| Snap beans | Sow outdoors | May 5 – Aug 3 |
| Sweet corn | Sow outdoors | May 5 – Jul 1 |
| Watermelon & cantaloupe | Sow outdoors | May 19 – Jun 19 |
| Okra | Sow outdoors | May 12 – Jun 4 |
| Peas | Sow outdoors (spring) | Mar 19 – May 4 |
| Potatoes | Plant outdoors (spring) | Mar 19 – May 19 |
| Onions | Start seeds indoors (spring) | Feb 5 – Mar 4 |
| Onions | Transplant outdoors (spring) | Apr 5 – May 4 |
| Broccoli | Start seeds indoors (spring) | Mar 1 – Apr 4 |
| Broccoli | Transplant outdoors (spring) | Apr 5 – May 4 |
| Broccoli | Start seeds indoors (fall) | Jun 21 – Jul 1 |
| Broccoli | Transplant outdoors (fall) | Jul 21 – Aug 1 |
| Cabbage | Start seeds indoors (spring) | Feb 19 – Mar 19 |
| Cabbage | Transplant outdoors (spring) | Mar 19 – Apr 19 |
| Cabbage | Start seeds indoors (fall) | Jun 11 – Jul 11 |
| Cabbage | Transplant outdoors (fall) | Jul 11 – Aug 11 |
| Leaf lettuce | Sow outdoors (spring) | Mar 19 – Jun 4 |
| Leaf lettuce | Sow outdoors (fall) | Jul 11 – Aug 27 |
| Spinach | Sow outdoors (spring) | Mar 12 – Apr 25 |
| Spinach | Sow outdoors (fall) | Jul 28 – Sep 1 |
| Radishes | Sow outdoors (spring) | Mar 19 – May 9 |
| Radishes | Sow outdoors (fall) | Jul 11 – Sep 11 |
| Kale | Sow outdoors (spring) | Apr 5 – Apr 25 |
| Kale | Sow outdoors (fall) | Jul 4 – Aug 11 |
| Carrots | Sow outdoors (spring) | Apr 19 – Jun 4 |
| Carrots | Sow outdoors (fall) | Jun 11 – Jul 27 |
| Garlic | Plant outdoors (fall) | Oct 11 – Nov 11 |
Where these dates come from
ZIP code 52099 is matched to the NOAA station Dubuque L&D 11, IA, 4.6 km away, at 620 ft elevation (3 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Dubuque L&D 11, IA (used) | 620 ft | Apr 19 | Oct 21 |
| Dubuque Rgnl Ap, IA | 1,056 ft | Apr 28 | Oct 11 |
| Galena, IL | 822 ft | Apr 26 | Oct 15 |
| Platteville, WI | 990 ft | Apr 30 | Oct 13 |
Frost dates near Dubuque
- Dubuque, IA 52004 · last Apr 19, first Oct 21
- East Dubuque, IL 61025 · last Apr 19, first Oct 21
- Kieler, WI 53812 · last Apr 19, first Oct 21
- Sinsinawa, WI 53824 · last Apr 28, first Oct 11
- Hazel Green, WI 53811 · last Apr 19, first Oct 21
- Peosta, IA 52068 · last Apr 28, first Oct 11
- Dickeyville, WI 53808 · last Apr 30, first Oct 13
- Durango, IA 52039 · last Apr 28, first Oct 11
Frequently asked questions
- When is the last frost in Dubuque, IA?
- For ZIP code 52099, the average last spring frost (32°F) is April 19, based on NOAA 1991-2020 climate normals for the Dubuque L&D 11, IA weather station. There is a 1-in-10 chance of a frost after May 4.
- When is the first frost in Dubuque, IA?
- The average first fall frost (32°F) is October 21. There is a 1-in-10 chance of frost by October 7, so tender plants are at risk from that point on.
- How long is the growing season in 52099?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 184 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.