Frost Dates for Columbia Falls, MT 59912
Last spring frost May 22 · First fall frost September 16 · 117 frost-free days · USDA Zone 5a
ZIP 59912 has about 15,800 people.
Short season: 117 frost-free days. Spring frost risk spans May 6–June 7 (32 days). Fall frost risk spans September 3–September 28 (25 days).
Frost probability for 59912
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | June 7 | May 22 | May 6 |
| Fall (first frost) | September 3 | September 16 | September 28 |
Dates come from NOAA 1971–2000 freeze probabilities at WHITEFISH (14.5 km away); the 50% date is the median year.
Which crops fit a 117-day season in Columbia Falls
In Columbia Falls (117 frost-free days, a short season), 33 of 56 planner crops fit outright, 15 get two plantings, 7 need an indoor start, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Apr 17 | Jun 5–Jun 12 | 75 | head-start: Even planted out Jun 5, the outdoor season is about 5 days short; choose an early variety or grow under cover. | — |
| Pepper | Apr 10 | Jun 5–Jun 12 | 75 | fits: 75 days to maturity, 75 available after Jun 5. | — |
| Lettuce | Mar 27 | Apr 24–May 1 | 152 | two-plantings: Plant Apr 24 and again by Jul 26; both mature before Sep 23. | Jul 26 |
| Carrots | — | May 1–May 8 | 159 | fits: 70 days to maturity, 159 available after May 1. | Jul 15 |
| Cucumber | May 1 | Jun 5–Jun 12 | 89 | fits: 60 days to maturity, 89 available after Jun 5. | Jun 20 |
| Beans | — | May 29–Jun 12 | 103 | fits: 60 days to maturity, 103 available after May 29. | Jun 27 |
| Peas | — | Mar 27–Jun 5 | 180 | fits: 65 days to maturity, 180 available after Mar 27. | Jul 6 |
| Zucchini | May 8 | Jun 5–Jun 12 | 89 | fits: 55 days to maturity, 89 available after Jun 5. | Jun 25 |
| Onion | Feb 27 | Apr 24–May 8 | 152 | fits: 100 days to maturity, 152 available after Apr 24. | — |
| Spinach | — | Mar 27–May 15 | 194 | two-plantings: Plant Mar 27 and again by Aug 14; both mature before Oct 7. | Aug 14 |
| Kale | Mar 13 | Apr 24–May 8 | 166 | two-plantings: Plant Apr 24 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Broccoli | Mar 27 | Apr 24–May 8 | 152 | fits: 80 days to maturity, 152 available after Apr 24. | Jun 21 |
| Cabbage | Mar 27 | Apr 24–May 8 | 166 | fits: 70 days to maturity, 166 available after Apr 24. | Jul 15 |
| Radish | — | Mar 27–Jun 19 | 180 | two-plantings: Plant Mar 27 and again by Aug 15; both mature before Sep 23. | Aug 15 |
| Beets | — | Mar 27–Jun 19 | 180 | two-plantings: Plant Mar 27 and again by Jul 16; both mature before Sep 23. | Jul 16 |
| Potatoes | — | May 8–May 15 | 138 | fits: 90 days to maturity, 138 available after May 8. | — |
| Garlic | — | Sep 16 | 222 | overwinter: Plant Sep 16 to Oct 7; harvest the following summer. | Oct 7 |
| Strawberry | — | Apr 17–Jun 12 | 173 | perennial: A perennial: plant Apr 17; it fruits from the following year and keeps producing for several years. | — |
| Corn | Apr 24 | May 29–Jun 5 | 89 | fits: 75 days to maturity, 89 available after May 29. | — |
| Pumpkin | May 8 | Jun 5–Jun 5 | 82 | head-start: Even planted out Jun 5, the outdoor season is about 18 days short; choose an early variety or grow under cover. | — |
| Cauliflower | Apr 10 | May 15–May 29 | 131 | fits: 75 days to maturity, 131 available after May 15. | Jun 26 |
| Swiss Chard | Mar 27 | May 8–May 8 | 138 | two-plantings: Plant May 8 and again by Jul 16; both mature before Sep 23. | Jul 16 |
| Arugula | — | Mar 27–Jun 19 | 194 | two-plantings: Plant Mar 27 and again by Aug 14; both mature before Oct 7. | Aug 14 |
| Brussel Sprouts | Mar 27 | Apr 24–May 8 | 166 | fits: 100 days to maturity, 166 available after Apr 24. | Jun 15 |
| Butternut Squash | May 8 | Jun 5–Jun 12 | 82 | head-start: Even planted out Jun 5, the outdoor season is about 18 days short; choose an early variety or grow under cover. | — |
| Eggplant | Apr 3 | Jun 5–Jun 12 | 75 | fits: 70 days to maturity, 75 available after Jun 5. | — |
| Okra | Apr 24 | May 29–Jun 5 | 96 | fits: 55 days to maturity, 96 available after May 29. | Jun 25 |
| Basil | Apr 17 | Jun 12–Jun 12 | 82 | fits: 60 days to maturity, 82 available after Jun 12. | Jun 20 |
| Cilantro | — | Apr 24–May 15 | 152 | two-plantings: Plant Apr 24 and again by Jul 21; both mature before Sep 23. | Jul 21 |
| Parsley | Mar 13 | May 29–Jun 5 | 117 | fits: 70 days to maturity, 117 available after May 29. | Jul 1 |
| Celery | Mar 13 | May 29–Jun 12 | 117 | head-start: Even planted out May 29, the outdoor season is about 3 days short; choose an early variety or grow under cover. | — |
| Scallions | Mar 13 | Apr 24–May 8 | 166 | two-plantings: Plant Apr 24 and again by Jul 25; both mature before Oct 7. | Jul 25 |
| Turnip | — | Apr 24–May 8 | 166 | two-plantings: Plant Apr 24 and again by Aug 4; both mature before Oct 7. | Aug 4 |
| Kohlrabi | — | Apr 10–Apr 24 | 180 | two-plantings: Plant Apr 10 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Bok Choy | Apr 24 | May 15–May 22 | 131 | two-plantings: Plant May 15 and again by Jul 26; both mature before Sep 23. | Jul 26 |
| Collards | Mar 13 | Apr 24–May 8 | 166 | two-plantings: Plant Apr 24 and again by Jul 25; both mature before Oct 7. | Jul 25 |
| Cantaloupe | May 8 | Jun 5–Jun 12 | 75 | head-start: Even planted out Jun 5, the outdoor season is about 10 days short; choose an early variety or grow under cover. | — |
| Chives | Feb 27 | May 29–Jun 5 | 131 | fits: 90 days to maturity, 131 available after May 29. | — |
| Dill | — | Mar 27–Jun 19 | 180 | two-plantings: Plant Mar 27 and again by Jul 16; both mature before Sep 23. | Jul 16 |
| Oregano | Mar 13 | May 29–Jun 5 | 131 | fits: 80 days to maturity, 131 available after May 29. | — |
| Rosemary | Feb 27 | May 29–Jun 5 | 117 | fits: 80 days to maturity, 117 available after May 29. | — |
| Sage | Mar 27 | May 29–Jun 5 | 131 | fits: 75 days to maturity, 131 available after May 29. | — |
| Thyme | Mar 13 | May 29–Jun 5 | 131 | fits: 90 days to maturity, 131 available after May 29. | — |
| Calendula | Apr 10 | May 8–May 22 | 138 | two-plantings: Plant May 8 and again by Jul 21; both mature before Sep 23. | Jul 21 |
| Cosmos | Apr 24 | May 22–Jun 5 | 103 | fits: 60 days to maturity, 103 available after May 22. | Jun 20 |
| Lavender | Feb 27 | May 22–Jun 5 | 138 | fits: 90 days to maturity, 138 available after May 22. | — |
| Marigolds | Apr 10 | May 22–May 29 | 103 | fits: 50 days to maturity, 103 available after May 22. | Jun 30 |
| Melons | May 8 | Jun 5–Jun 12 | 75 | head-start: Even planted out Jun 5, the outdoor season is about 10 days short; choose an early variety or grow under cover. | — |
| Mint | — | May 22–Jun 5 | 138 | fits: 90 days to maturity, 138 available after May 22. | — |
| Nasturtiums | Apr 24 | May 22–May 29 | 103 | fits: 55 days to maturity, 103 available after May 22. | Jun 25 |
| Pole Beans | — | May 29–Jun 12 | 96 | fits: 65 days to maturity, 96 available after May 29. | Jun 15 |
| Spaghetti Squash | May 8 | Jun 5–Jun 12 | 82 | head-start: Even planted out Jun 5, the outdoor season is about 8 days short; choose an early variety or grow under cover. | — |
| Sunflowers | — | May 22–Jun 5 | 103 | fits: 70 days to maturity, 103 available after May 22. | Jun 10 |
| Tomatillos | Mar 27 | May 29–Jun 5 | 82 | fits: 75 days to maturity, 82 available after May 29. | — |
| Watermelon | May 8 | May 29–Jun 5 | 82 | fits: 80 days to maturity, 82 available after May 29. | — |
| Yellow Squash | May 8 | Jun 5–Jun 12 | 89 | fits: 55 days to maturity, 89 available after Jun 5. | Jun 25 |
| Zinnias | Apr 24 | May 22–Jun 5 | 103 | fits: 60 days to maturity, 103 available after May 22. | Jun 20 |
Month by month in Columbia Falls
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start indoors: Chives (Feb 27), Lavender (Feb 27), Onion (Feb 27), Rosemary (Feb 27). |
| March | Start indoors: Celery (Mar 13), Collards (Mar 13), Kale (Mar 13), Oregano (Mar 13), Parsley (Mar 13), Scallions (Mar 13), +8 more. Direct sow from: Arugula (Mar 27), Beets (Mar 27), Dill (Mar 27), Peas (Mar 27), Radish (Mar 27), Spinach (Mar 27). |
| April | Start indoors: Eggplant (Apr 3), Calendula (Apr 10), Cauliflower (Apr 10), Marigolds (Apr 10), Pepper (Apr 10), Basil (Apr 17), +7 more. Direct sow from: Kohlrabi (Apr 10), Cilantro (Apr 24), Turnip (Apr 24). Transplant from: Broccoli (Apr 24), Brussel Sprouts (Apr 24), Cabbage (Apr 24), Collards (Apr 24), Kale (Apr 24), Lettuce (Apr 24), +2 more. Plant: Strawberry (Apr 17). |
| May | Start indoors: Cucumber (May 1), Butternut Squash (May 8), Cantaloupe (May 8), Melons (May 8), Pumpkin (May 8), Spaghetti Squash (May 8), +3 more. Direct sow from: Carrots (May 1), Potatoes (May 8), Sunflowers (May 22), Beans (May 29), Pole Beans (May 29). Transplant from: Calendula (May 8), Swiss Chard (May 8), Bok Choy (May 15), Cauliflower (May 15), Cosmos (May 22), Lavender (May 22), +15 more. Last frost around May 22. |
| June | Transplant from: Butternut Squash (Jun 5), Cantaloupe (Jun 5), Cucumber (Jun 5), Eggplant (Jun 5), Melons (Jun 5), Pepper (Jun 5), +6 more. Last sowing dates: Sunflowers (Jun 10), Brussel Sprouts (Jun 15), Pole Beans (Jun 15), Basil (Jun 20), Cosmos (Jun 20), Cucumber (Jun 20), +9 more. |
| July | Last sowing dates: Parsley (Jul 1), Peas (Jul 6), Cabbage (Jul 15), Carrots (Jul 15), Beets (Jul 16), Dill (Jul 16), +9 more. |
| August | Last sowing dates: Turnip (Aug 4), Arugula (Aug 14), Spinach (Aug 14), Radish (Aug 15). |
| September | Direct sow from: Garlic (Sep 16). First frost around September 16. |
| October | Last sowing dates: Garlic (Oct 7). |
| 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 Columbia Falls, MT (ZIP 59912)?
The median last spring frost date for Columbia Falls, MT (ZIP code 59912) is around May 22. 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 May 6; one in ten it runs past June 7.
What is the first fall frost date in Columbia Falls, MT?
The median first fall frost date for Columbia Falls, MT is around September 16. 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 3 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Columbia Falls, MT?
The frost-free growing season in Columbia Falls is about 117 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 Columbia Falls (117 frost-free days, a short season), 33 of 56 planner crops fit outright, 15 get two plantings, 7 need an indoor start, 1 crop is perennial.
What USDA hardiness zone is Columbia Falls, MT?
Columbia Falls, 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 Columbia Falls, MT?
Start tomatoes indoors Apr 17 and plant out Jun 5 in Columbia Falls. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Columbia Falls?
Two: plant Apr 24 and again by Jul 26; both mature before Sep 23.
When do I plant garlic in Columbia Falls?
Sep 16 to Oct 7; it overwinters and is ready the following summer.
Can I grow Celery in Columbia Falls?
Yes, with help. Even planted out May 29, the outdoor season is about 3 days short; choose an early variety or grow under cover.
Which nearby ZIP has a longer season?
Polson (ZIP 59860) has 144 frost-free days, 27 more than Columbia Falls (ZIP 59912). See Polson ZIP 59860 frost dates
Nearby and related
- Frost dates for Whitefish, MT 59937 (15 mi)
- Frost dates for Kalispell, MT 59901 (18.1 mi)
- Frost dates for Polson, MT 59860 (50.1 mi)
- Frost dates for Libby, MT 59923 (53.5 mi)
- Frost dates for Missoula, MT 59808 (100.8 mi)
- When to plant in MT
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