Frost Dates for Billings, MT 59102
Last spring frost May 8 · First fall frost September 27 · 142 frost-free days · USDA Zone 5a
ZIP 59102 has about 48,000 people, the largest of 4 ZIP codes in Billings.
Moderate season: 142 frost-free days. Spring frost risk spans April 22–May 24 (32 days). Fall frost risk spans September 14–October 10 (26 days).
Frost probability for 59102
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | May 24 | May 8 | April 22 |
| Fall (first frost) | September 14 | September 27 | October 10 |
Dates come from NOAA 1971–2000 freeze probabilities at BILLINGS WTP (7.8 km away); the 50% date is the median year.
Frost dates by ZIP code in Billings, MT
| ZIP | Last spring frost (50%) | First fall frost (50%) | Zone |
|---|---|---|---|
| 59102 | May 8 | September 27 | 5a |
| 59101 | May 8 | September 27 | 5a |
| 59105 | May 8 | September 27 | 5a |
| 59106 | May 8 | September 27 | 5a |
Which crops fit a 142-day season in Billings
In Billings (142 frost-free days, a moderate season), 38 of 56 planner crops fit outright, 17 get two plantings, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Apr 3 | May 22–May 29 | 100 | fits: 80 days to maturity, 100 available after May 22. | May 28 |
| Pepper | Mar 27 | May 22–May 29 | 100 | fits: 75 days to maturity, 100 available after May 22. | Jun 2 |
| Lettuce | Mar 13 | Apr 10–Apr 17 | 177 | two-plantings: Plant Apr 10 and again by Aug 6; both mature before Oct 4. | Aug 6 |
| Carrots | — | Apr 17–Apr 24 | 184 | fits: 70 days to maturity, 184 available after Apr 17. | Jul 26 |
| Cucumber | Apr 17 | May 22–May 29 | 114 | fits: 60 days to maturity, 114 available after May 22. | Jul 1 |
| Beans | — | May 15–May 29 | 128 | fits: 60 days to maturity, 128 available after May 15. | Jul 8 |
| Peas | — | Mar 13–May 22 | 205 | fits: 65 days to maturity, 205 available after Mar 13. | Jul 17 |
| Zucchini | Apr 24 | May 22–May 29 | 114 | fits: 55 days to maturity, 114 available after May 22. | Jul 6 |
| Onion | Feb 13 | Apr 10–Apr 24 | 177 | fits: 100 days to maturity, 177 available after Apr 10. | — |
| Spinach | — | Mar 13–May 1 | 219 | two-plantings: Plant Mar 13 and again by Aug 25; both mature before Oct 18. | Aug 25 |
| Kale | Feb 27 | Apr 10–Apr 24 | 191 | two-plantings: Plant Apr 10 and again by Aug 10; both mature before Oct 18. | Aug 10 |
| Broccoli | Mar 13 | Apr 10–Apr 24 | 177 | fits: 80 days to maturity, 177 available after Apr 10. | Jul 2 |
| Cabbage | Mar 13 | Apr 10–Apr 24 | 191 | fits: 70 days to maturity, 191 available after Apr 10. | Jul 26 |
| Radish | — | Mar 13–Jun 5 | 205 | two-plantings: Plant Mar 13 and again by Aug 26; both mature before Oct 4. | Aug 26 |
| Beets | — | Mar 13–Jun 5 | 205 | two-plantings: Plant Mar 13 and again by Jul 27; both mature before Oct 4. | Jul 27 |
| Potatoes | — | Apr 24–May 1 | 163 | fits: 90 days to maturity, 163 available after Apr 24. | — |
| Garlic | — | Sep 27 | 247 | overwinter: Plant Sep 27 to Oct 18; harvest the following summer. | Oct 18 |
| Strawberry | — | Apr 3–May 29 | 198 | perennial: A perennial: plant Apr 3; it fruits from the following year and keeps producing for several years. | — |
| Corn | Apr 10 | May 15–May 22 | 114 | fits: 75 days to maturity, 114 available after May 15. | Jun 9 |
| Pumpkin | Apr 24 | May 22–May 22 | 107 | fits: 100 days to maturity, 107 available after May 22. | — |
| Cauliflower | Mar 27 | May 1–May 15 | 156 | fits: 75 days to maturity, 156 available after May 1. | Jul 7 |
| Swiss Chard | Mar 13 | Apr 24–Apr 24 | 163 | two-plantings: Plant Apr 24 and again by Jul 27; both mature before Oct 4. | Jul 27 |
| Arugula | — | Mar 13–Jun 5 | 219 | two-plantings: Plant Mar 13 and again by Aug 25; both mature before Oct 18. | Aug 25 |
| Brussel Sprouts | Mar 13 | Apr 10–Apr 24 | 191 | fits: 100 days to maturity, 191 available after Apr 10. | Jun 26 |
| Butternut Squash | Apr 24 | May 22–May 29 | 107 | fits: 100 days to maturity, 107 available after May 22. | — |
| Eggplant | Mar 20 | May 22–May 29 | 100 | fits: 70 days to maturity, 100 available after May 22. | Jun 7 |
| Okra | Apr 10 | May 15–May 22 | 121 | fits: 55 days to maturity, 121 available after May 15. | Jul 6 |
| Basil | Apr 3 | May 29–May 29 | 107 | fits: 60 days to maturity, 107 available after May 29. | Jul 1 |
| Cilantro | — | Apr 10–May 1 | 177 | two-plantings: Plant Apr 10 and again by Aug 1; both mature before Oct 4. | Aug 1 |
| Parsley | Feb 27 | May 15–May 22 | 142 | fits: 70 days to maturity, 142 available after May 15. | Jul 12 |
| Celery | Feb 27 | May 15–May 29 | 142 | fits: 120 days to maturity, 142 available after May 15. | May 23 |
| Scallions | Feb 27 | Apr 10–Apr 24 | 191 | two-plantings: Plant Apr 10 and again by Aug 5; both mature before Oct 18. | Aug 5 |
| Turnip | — | Apr 10–Apr 24 | 191 | two-plantings: Plant Apr 10 and again by Aug 15; both mature before Oct 18. | Aug 15 |
| Kohlrabi | — | Mar 27–Apr 10 | 205 | two-plantings: Plant Mar 27 and again by Aug 10; both mature before Oct 18. | Aug 10 |
| Bok Choy | Apr 10 | May 1–May 8 | 156 | two-plantings: Plant May 1 and again by Aug 6; both mature before Oct 4. | Aug 6 |
| Collards | Feb 27 | Apr 10–Apr 24 | 191 | two-plantings: Plant Apr 10 and again by Aug 5; both mature before Oct 18. | Aug 5 |
| Cantaloupe | Apr 24 | May 22–May 29 | 100 | fits: 85 days to maturity, 100 available after May 22. | May 23 |
| Chives | Feb 13 | May 15–May 22 | 156 | fits: 90 days to maturity, 156 available after May 15. | — |
| Dill | — | Mar 13–Jun 5 | 205 | two-plantings: Plant Mar 13 and again by Jul 27; both mature before Oct 4. | Jul 27 |
| Oregano | Feb 27 | May 15–May 22 | 156 | fits: 80 days to maturity, 156 available after May 15. | — |
| Rosemary | Feb 13 | May 15–May 22 | 142 | fits: 80 days to maturity, 142 available after May 15. | — |
| Sage | Mar 13 | May 15–May 22 | 156 | fits: 75 days to maturity, 156 available after May 15. | — |
| Thyme | Feb 27 | May 15–May 22 | 156 | fits: 90 days to maturity, 156 available after May 15. | — |
| Calendula | Mar 27 | Apr 24–May 8 | 163 | two-plantings: Plant Apr 24 and again by Aug 1; both mature before Oct 4. | Aug 1 |
| Cosmos | Apr 10 | May 8–May 22 | 128 | fits: 60 days to maturity, 128 available after May 8. | Jul 1 |
| Lavender | Feb 13 | May 8–May 22 | 163 | fits: 90 days to maturity, 163 available after May 8. | — |
| Marigolds | Mar 27 | May 8–May 15 | 128 | two-plantings: Plant May 8 and again by Jul 11; both mature before Sep 13. | Jul 11 |
| Melons | Apr 24 | May 22–May 29 | 100 | fits: 85 days to maturity, 100 available after May 22. | May 23 |
| Mint | — | May 8–May 22 | 163 | fits: 90 days to maturity, 163 available after May 8. | — |
| Nasturtiums | Apr 10 | May 8–May 15 | 128 | two-plantings: Plant May 8 and again by Jul 6; both mature before Sep 13. | Jul 6 |
| Pole Beans | — | May 15–May 29 | 121 | fits: 65 days to maturity, 121 available after May 15. | Jun 26 |
| Spaghetti Squash | Apr 24 | May 22–May 29 | 107 | fits: 90 days to maturity, 107 available after May 22. | May 25 |
| Sunflowers | — | May 8–May 22 | 128 | fits: 70 days to maturity, 128 available after May 8. | Jun 21 |
| Tomatillos | Mar 13 | May 15–May 22 | 107 | fits: 75 days to maturity, 107 available after May 15. | Jun 2 |
| Watermelon | Apr 24 | May 15–May 22 | 107 | fits: 80 days to maturity, 107 available after May 15. | May 28 |
| Yellow Squash | Apr 24 | May 22–May 29 | 114 | fits: 55 days to maturity, 114 available after May 22. | Jul 6 |
| Zinnias | Apr 10 | May 8–May 22 | 128 | fits: 60 days to maturity, 128 available after May 8. | Jul 1 |
Month by month in Billings
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start indoors: Chives (Feb 13), Lavender (Feb 13), Onion (Feb 13), Rosemary (Feb 13), Celery (Feb 27), Collards (Feb 27), +5 more. |
| March | Start indoors: Broccoli (Mar 13), Brussel Sprouts (Mar 13), Cabbage (Mar 13), Lettuce (Mar 13), Sage (Mar 13), Swiss Chard (Mar 13), +6 more. Direct sow from: Arugula (Mar 13), Beets (Mar 13), Dill (Mar 13), Peas (Mar 13), Radish (Mar 13), Spinach (Mar 13), +1 more. |
| April | Start indoors: Basil (Apr 3), Tomato (Apr 3), Bok Choy (Apr 10), Corn (Apr 10), Cosmos (Apr 10), Nasturtiums (Apr 10), +11 more. Direct sow from: Cilantro (Apr 10), Turnip (Apr 10), Carrots (Apr 17), Potatoes (Apr 24). Transplant from: Broccoli (Apr 10), Brussel Sprouts (Apr 10), Cabbage (Apr 10), Collards (Apr 10), Kale (Apr 10), Lettuce (Apr 10), +4 more. Plant: Strawberry (Apr 3). |
| May | Direct sow from: Sunflowers (May 8), Beans (May 15), Pole Beans (May 15). Transplant from: Bok Choy (May 1), Cauliflower (May 1), Cosmos (May 8), Lavender (May 8), Marigolds (May 8), Mint (May 8), +25 more. Last frost around May 8. Last sowing dates: Cantaloupe (May 23), Celery (May 23), Melons (May 23), Spaghetti Squash (May 25), Tomato (May 28), Watermelon (May 28). |
| June | Last sowing dates: Pepper (Jun 2), Tomatillos (Jun 2), Eggplant (Jun 7), Corn (Jun 9), Sunflowers (Jun 21), Brussel Sprouts (Jun 26), +1 more. |
| July | Last sowing dates: Basil (Jul 1), Cosmos (Jul 1), Cucumber (Jul 1), Zinnias (Jul 1), Broccoli (Jul 2), Nasturtiums (Jul 6), +13 more. |
| August | Last sowing dates: Calendula (Aug 1), Cilantro (Aug 1), Collards (Aug 5), Scallions (Aug 5), Bok Choy (Aug 6), Lettuce (Aug 6), +6 more. |
| September | Direct sow from: Garlic (Sep 27). First frost around September 27. |
| October | Last sowing dates: Garlic (Oct 18). |
| November | Clean up spent plants. Add compost to beds. Rest, review, and plan next year's garden. |
| December | Clean up spent plants. Add compost to beds. Rest, review, and plan next year's garden. |
Frequently Asked Questions
What is the last frost date for Billings, MT (ZIP 59102)?
The median last spring frost date for Billings, MT (ZIP code 59102) is around May 8. This is the 50th-percentile date — meaning half of all years see frost end before this date. Use the 10% and 90% dates to understand the full range of risk in your area. One year in ten frost ends before April 22; one in ten it runs past May 24.
What is the first fall frost date in Billings, MT?
The median first fall frost date for Billings, MT is around September 27. Plan to harvest or protect frost-sensitive crops like tomatoes and peppers at least a week before this date to avoid losses. The first frost arrives around September 14 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Billings, MT?
The frost-free growing season in Billings is about 142 days. This window — from your last spring frost to your first fall frost — is when warm-season vegetables thrive. Cold-hardy crops like kale, spinach, and peas can extend your season by weeks on either side. In Billings (142 frost-free days, a moderate season), 38 of 56 planner crops fit outright, 17 get two plantings, 1 crop is perennial.
What USDA hardiness zone is Billings, MT?
Billings, MT is in USDA hardiness zone 5a (2023 USDA Plant Hardiness Zone Map). Zones come from the average coldest winter temperature, so they tell you which perennials survive the winter; the frost dates on this page tell you when to plant.
When should I start tomatoes indoors in Billings, MT?
Start tomatoes indoors Apr 3 and plant out May 22 in Billings. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Billings?
Two: plant Apr 10 and again by Aug 6; both mature before Oct 4.
When do I plant garlic in Billings?
Sep 27 to Oct 18; it overwinters and is ready the following summer.
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