When is the last frost in Bozeman, MT?

The average last spring frost (50% probability of 32°F) in Bozeman is around May 23, based on NOAA/NCEI 1991–2020 normals at the Bozeman 6 W Exp Farm, MT station (2.4 mi away). Half of years it falls outside that date, so wait 1–2 weeks past it before setting out frost-tender plants.

When is the first fall frost in Bozeman?

The average first fall frost in Bozeman, MT is around September 23, giving roughly a 123-day frost-free growing season.

What planting zone is Bozeman, MT?

Bozeman is in USDA plant hardiness zone 5a (average annual extreme minimum temperature -20 to -15°F), from the 2023 USDA Plant Hardiness Zone Map.

What is the weather like in Bozeman?

In Bozeman, MT the warmest month is July (avg high 82.1°F) and the coldest is December (avg low 14.5°F). It averages about 20″ of precipitation a year and 91.3″ of snow.

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Bozeman, MT Planting Calendar & Frost Dates

USDA hardiness zone 5a · ZIP 59718 · elevation 1498′ · NOAA & USDA data

Bozeman is in USDA hardiness zone 5a (winters can dip to -20 to -15°F), with a growing season of about 123 days between the average last spring frost (May 23) and first fall frost (September 23). The warmest month is July (avg high 82.1°F); the coldest is December (avg low 14.5°F). It averages 20″ of precipitation a year and 91.3″ of snow, mostly mid-winter. Start cool-season crops several weeks before the last frost; wait until after it for tomatoes, peppers and other tender crops.

Hardiness zone

min temp -20 to -15°F

Last spring frost

May 23

avg (50% prob, 32°F)

First fall frost

September 23

avg (50% prob, 32°F)

Growing season

123 days

frost-free window

Warmest month

July

avg high 82.1°F

Month-by-month typical weather in Bozeman

Average conditions from the NOAA/NCEI 1991–2020 U.S. Climate Normals at Bozeman Montana State Univ, MT (6.2 mi away). Temperatures °F, precipitation & snow in inches.

Month	Avg high	Avg low	Mean	Precip (in)	Snow (in)
January	34.2	15.1	24.6	0.9	12.7
February	36.8	16.6	26.7	0.8	13
March	46.1	23.9	35	1.4	13.1
April	54.5	30.5	42.5	2.5	12.9
May	63.2	38.8	51	2.9	3.6
June	71.7	45.6	58.6	3.3	0.8
July	82.1	51.7	66.9	1.3	0
August	81.3	50	65.6	1.3	0.1
September	71.4	42.4	56.9	1.4	0.4
October	57.3	32.4	44.9	1.8	6
November	42.3	22.2	32.3	1.3	12.5
December	33.3	14.5	23.9	1	16.2

What to plant when in Bozeman

Crop	Season	What to do & when
Tomatoes	warm	Start seeds indoors: April 11 · Transplant out: May 30
Peppers	warm	Start seeds indoors: March 28 · Transplant out: June 6
Cucumbers	warm	Direct sow: May 30
Zucchini / squash	warm	Direct sow: May 30
Bush beans	warm	Direct sow: May 30
Sweet corn	warm	Direct sow: May 30
Basil	warm	Transplant out: May 30
Peas	cool	Sow (spring): April 18 · Sow (fall): July 29
Spinach	cool	Sow (spring): April 11 · Sow (fall): July 29
Lettuce	cool	Sow (spring): April 25 · Sow (fall): July 29
Kale	cool	Transplant (spring): May 2 · Sow (fall): July 15
Broccoli	cool	Transplant (spring): May 9
Carrots	cool	Sow (spring): May 2 · Sow (fall): July 15
Onions	cool	Transplant (spring): April 25
Potatoes	cool	Plant seed potatoes: May 9
Radishes	cool	Sow (spring): April 25 · Sow (fall): August 12

Dates are computed from Bozeman's average frost dates using standard cool-/warm-season timing. They're a starting point — a cold spring, a warm microclimate, or a fast-maturing variety can shift them by a week or two.

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Gear that helps you plant on time

Some links below are Amazon affiliate links (tag theboringthin-20). If you buy through them we may earn a small commission at no extra cost to you — it keeps this almanac free. We only list generic, genuinely-useful categories.

Soil thermometer →Know when the ground is warm enough to sow — the honest signal, not the calendar.Seed-starting trays + dome →Start tomatoes & peppers indoors on the schedule below.Seedling heat mat →Warms the soil for faster, more even germination indoors.Floating row cover / frost cloth →Buys you 4–8°F to beat an early or late frost.Raised garden bed kit →Warms and drains faster in spring than in-ground soil.Garden gloves →Basic kit for transplant day.

Nearby cities in Montana

Billings, MT Great Falls, MT Missoula, MT

Sources & method. Hardiness zone: 2023 USDA Plant Hardiness Zone Map (PRISM Climate Group, Oregon State University). Frost dates & growing season: NOAA/NCEI 1991–2020 U.S. Climate Normals, nearest station with published freeze normals — Bozeman 6 W Exp Farm, MT, 2.4 mi (confidence: high). Monthly weather normals: Bozeman Montana State Univ, MT, 6.2 mi (confidence: high). ZIP centroid from U.S. Census 2023 ZCTA data. Frost dates are the 50%-probability date — half of years frost occurs outside the stated date. Nothing here is invented; where the nearest station is far, we say so. Last updated 2026-07-22.