Billings’ first fall freeze lands somewhere between October 1 and October 14 most years, and that narrow window is the whole ballgame for a Montana tomato patch. Count backward from it using a variety’s days-to-maturity and a mid-to-late-May transplant date, and the field splits fast: 55-to-68-day types clear the season with a month to spare, while 72-to-78-day types finish, but just barely. Everything below is built on that math, not a promise.
What this comes down to in Montana
A tomato ripens here if it finishes its days-to-maturity count before the first fall freeze reaches the garden, and at Billings that freeze arrives, per NOAA’s 1991-2020 climate normals, sometime between October 1 and October 14. Work backward from that window using a variety’s published days-to-maturity and a transplant date of mid-May to late-May, which is the window this state’s spring frost pattern allows, and the cultivars that actually deliver ripe fruit here sort into two groups: a wide set of 55-to-68-day types that clear the season with a month or more to spare, and a shorter set of 72-to-78-day types that still finish, but with a much tighter margin.
The days-to-maturity number on a seed packet is counted from transplant, not from seed, and it shifts by a week or two depending on how warm the season runs. Treat every date below as a range built on a catalogue figure crossed with the Billings frost window, not as a guarantee for your own yard.
Sakura
Sakura needs about 55 days from transplant, the shortest count on this list, and produces small red cherry tomatoes in long clusters. Set out mid-May to late-May, it ripens by mid-July and leaves about 75 days of margin before the Billings fall frost window opens, which makes it one of the safest bets in the state. It also resists nematodes, tomato mosaic virus, and both common races of fusarium wilt, so a poor soil history costs it little.
Sun Gold
Sun Gold matures in about 57 days and produces small tangerine-orange cherry tomatoes with a thin skin that splits if rain follows a dry spell. It ripens by mid-July from a mid-to-late-May transplant, with about 73 days of margin before frost, and carries resistance to tobacco mosaic virus and one race of fusarium wilt.
Supersweet 100
At 60 days from transplant, Supersweet 100 sets heavy clusters of small round red cherry tomatoes on a vigorous vine that needs a tall cage or trellis. It ripens by late July with about 70 days of margin before the first fall freeze, and its resistance to verticillium wilt and fusarium wilt race 1 matters most in a bed that has carried tomatoes for several years running.
Amalfi
Amalfi runs 68 days from transplant and produces elongated red plum tomatoes with dense flesh, bred for sauce rather than slicing, on a compact determinate plant that needs less staking than the vining types above. It ripens by late July with about 62 days of margin before frost, and its resistance to early blight and late blight is worth having in a wet year.
Cherokee Purple
Cherokee Purple takes about 72 days from transplant and produces large, slightly flattened beefsteak tomatoes with a dusky purple-pink skin, prized for flavor over yield. It ripens by early August with about 58 days of margin before the first fall freeze at Billings, and it carries no listed disease resistance, so it rewards a clean bed and good airflow more than the hybrids around it.
Big Beef Plus
Big Beef Plus also needs about 72 days from transplant and produces large, smooth red beefsteak tomatoes suited to slicing. It ripens by early August with roughly 58 days of margin before frost, and its resistance to nematodes, gray leaf spot, and tomato mosaic virus makes it a steadier choice than Cherokee Purple in a garden with a history of leaf disease.
Tiren
Tiren runs 75 days from transplant and produces elongated red plum-shaped fruit with dense, low-moisture flesh built for sauce and canning. It ripens by early August with about 55 days of margin before the Billings fall frost window, and its resistance to verticillium wilt, tomato mosaic virus, and fusarium wilt race 1 makes it a reasonable long-season pick where those diseases have shown up before.
San Marzano II
San Marzano II is the longest-season variety on this list at 78 days from transplant, producing the classic long, narrow, thick-walled paste tomato used for canning. Set out mid-May to late-May, it ripens by early August with about 52 days of margin before the first fall freeze at Billings, which is enough in a normal year but leaves little room if the season runs cold or the transplant goes in late.
| Variety | Days from transplant | First ripe | Margin before Billings frost |
|---|---|---|---|
| Sakura | 55 | mid-July | ~75 days |
| Sun Gold | 57 | mid-July | ~73 days |
| Supersweet 100 | 60 | late July | ~70 days |
| Amalfi | 68 | late July | ~62 days |
| Cherokee Purple | 72 | early August | ~58 days |
| Big Beef Plus | 72 | early August | ~58 days |
| Tiren | 75 | early August | ~55 days |
| San Marzano II | 78 | early August | ~52 days |
Working it out for your own garden
The method behind every date above works for any variety not on this list, as long as you have its catalogue days-to-maturity figure.
Start from the frost window
NOAA’s 1991-2020 climate normals give two fixed points for Billings: a last spring freeze falling between April 29 and May 10, and a first fall freeze falling between October 1 and October 14. Tomato transplants need the soil to have warmed past that spring freeze risk, which is why the safe transplant window for this reference city sits at mid-May to late-May rather than right on the frost date itself. For the full week-by-week logic behind that window, see Tomato Planting Dates in Montana: Counting Back From Your Frost Window.
Run the days-to-maturity math
From there, the math is addition, not subtraction. Take Sakura, rated at 55 days from transplant. Set out mid-May to late-May, add 55 days, and first ripe fruit lands in mid-July, about 75 days before the earliest possible start of the fall freeze window on October 1. That gap is why a 55-day variety reads as low-risk almost anywhere in the state.
Now run the same math on San Marzano II, rated at 78 days. A mid-May to late-May transplant plus 78 days lands first ripe fruit in early August, which still leaves about 52 days before October 1 at Billings. That margin holds in a normal year at a mild-valley location like Billings, but the same variety planted at a higher, colder site with a shorter built-in season has far less room. Push the transplant back a week for a late, cold spring, and a 78-day paste tomato can run out of season before it runs out of green fruit.
What changes across the state
Billings sits in one of Montana’s milder valleys, and the NOAA frost dates above describe that location specifically, not the state as a whole. The USDA Plant Hardiness Zone Map places Montana across zones 3a to 6a, a five-zone spread within one state that tells you how much elevation and terrain can move these numbers around.
Elevation and mountain valleys
A higher-elevation valley can run a full month or more behind Billings on both ends of the season, pushing the last spring freeze later into the calendar and pulling the first fall freeze earlier. Cold air also drains downhill and pools in a valley bottom overnight, so a garden a few hundred feet lower than its surroundings can frost on a night when a garden on the slope above it does not. Mountain valleys are also where a frost can arrive in almost any month of the growing season, which is why the margins in the table above should be read as a Billings-area baseline, not a statewide promise.
Plains, wind, and local exposure
The plains and lower valleys of the eastern and central part of the state track closer to the Billings pattern, though with their own county-by-county variation. Wind exposure matters on top of elevation: a site with no windbreak loses heat faster on a clear, still night than a sheltered one nearby, which is part of why two gardens at similar elevation can still report different frost dates in the same week. None of this changes which cultivar matures fastest, but it does change how much of that variety’s margin actually survives contact with your specific ground.
The mistakes this state punishes
Cold soil, warm air
The most common mistake is transplanting on a warm afternoon in early May because the air feels like summer, when the soil four to six inches down is still cold. A tomato set into cold soil stalls for two or three weeks while it recovers, which erases most of the margin a short-season variety like Sakura or Sun Gold was supposed to give. Wait for the soil itself to warm, not just the air, and hold inside the mid-May to late-May window this state’s frost pattern allows. This step, and the general bed prep it assumes, is covered in more depth in growing tomatoes in Montana.
Choosing too long a season
The second mistake is picking a 75-to-78-day variety like Tiren or San Marzano II for a garden that does not actually sit in a Billings-like microclimate. A variety with 52 days of margin at Billings can have close to none at a higher, colder site, and there is no way to get those days back once the season is already running. If you are not certain your site tracks the reference city closely, choose from the 55-to-68-day group instead and treat the longer-season paste tomatoes as a bonus in a warm year, not a plan.
Ignoring pest and disease pressure
The third mistake is assuming the disease resistance codes on a seed packet cover everything. Nematode, fusarium, verticillium, and blight resistance only protect against the specific pathogen named, and what actually threatens a given planting shifts through the season. See Tomato Pests in Montana: Which Ones Actually Show Up Here for what to watch for once fruit starts setting. Skipping that check and assuming resistance codes cover everything is how an otherwise well-timed planting still comes up short at harvest.
Checking this against your county
Every figure above is anchored to Billings, and Montana’s counties spread across a five-zone range on the USDA Plant Hardiness Zone Map, so treat this page as a starting point, not an instruction, for your own yard. For a frost date and season length specific to your county, contact your local office through Montana State University Extension, and cross-check the recommendation against your own garden’s recent frost history before committing a full bed to a 75-day-plus variety.
Common questions
Can I still grow a 90-day tomato in Montana?
Not reliably from a normal outdoor transplant in most of the state. None of the shorter-season cultivars above run past 78 days for a reason, and even San Marzano II at 78 days only clears the Billings frost window by about 52 days of margin. A 90-day type would need a much larger head start than a standard transplant provides, and it would still be a gamble in a cold year.
Do I need to start seeds indoors or can I direct-sow tomatoes?
Direct-sowing tomato seed outdoors does not work in this climate. Every variety and date on this page assumes a transplant already several weeks old going into the ground during the mid-May to late-May window, not a seed sown where it will grow.
What happens if I plant a long-season variety and frost comes early?
Green fruit left on the vine when a hard freeze hits will not ripen further outdoors, though many gardeners pull whole plants before the freeze and let mature-green fruit finish indoors on a windowsill. That works best on fruit that has already started to turn, not on fruit that is still fully green and small.
Are cherry tomatoes really safer than Beefsteaks here?
Not because they are cherry tomatoes specifically, but because the cherry varieties on this list, Sakura, Sun Gold, and Supersweet 100, happen to carry the shortest days-to-maturity ratings. A beefsteak-type bred for a short season would carry the same margin; days-to-maturity is what drives the risk, not fruit size or type.