When Is the Last Frost?

Lonepine, MT frost dates

Last spring frostMay 15median date
First fall frostSep 28median date
Growing season136 daysfrost-free
Hardiness zone6aZone 6a

How Lonepine compares

Frost probability

Last spring frost
Chance of frost afterDate
90% (early)May 3
50% (median)May 15
10% (safe for tender plants)June 1
First fall frost
Chance of frost beforeDate
10% (early)September 13
50% (median)September 28
90% (late)October 11

Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.

Planting calendar for Lonepine, MT

Lonepine, MT frost dates — last frost May 15, first frost Sep 28, zone 6a. whenisthelastfrost.com

Crop
JFMAMJJASOND
Start indoors: Feb 20 to Mar 6Transplant outside: Apr 17 to May 1
Start indoors: Mar 6 to Mar 20Transplant outside: May 29 to Jun 12
Start indoors: Mar 6 to Mar 20Transplant outside: May 29 to Jun 12
Start indoors: Mar 20 to Apr 3Transplant outside: May 22 to Jun 5
Start indoors: Mar 20 to Apr 3Transplant outside: Apr 24 to May 8Sow outdoors: Apr 17 to May 22Plant for fall: Aug 3 to Aug 31
Start indoors: Mar 20 to Apr 3Transplant outside: Apr 17 to May 1Sow outdoors: Apr 17 to May 1Plant for fall: Jul 20 to Aug 10
Start indoors: Mar 20 to Apr 3Transplant outside: May 1 to May 15Plant for fall: Jun 22 to Jul 13
Start indoors: Mar 20 to Apr 3Transplant outside: Apr 24 to May 8Plant for fall: Jun 22 to Jul 13
Start indoors: Mar 20 to Apr 3Transplant outside: May 1 to May 15Plant for fall: Jun 22 to Jul 13
Start indoors: Apr 3 to Apr 17Transplant outside: Jun 5 to Jun 19Sow outdoors: Jun 5 to Jun 19
Start indoors: Apr 3 to Apr 17Transplant outside: May 22 to Jun 5
Sow outdoors: Apr 3 to Apr 24Plant for fall: Jul 6 to Jul 27
Sow outdoors: Apr 3 to Apr 24Plant for fall: Aug 3 to Aug 24
Sow outdoors: Apr 10 to May 22Plant for fall: Aug 17 to Sep 7
Start indoors: Apr 17 to Apr 24Transplant outside: May 29 to Jun 5Sow outdoors: May 22 to Jun 5Plant for fall: Jul 13 to Jul 27
Start indoors: Apr 17 to Apr 24Sow outdoors: May 22 to Jun 5Plant for fall: Jul 20 to Aug 3
Start indoors: Apr 17 to Apr 24Sow outdoors: May 22 to Jun 5
Start indoors: Apr 17 to Apr 24Transplant outside: May 29 to Jun 12
Sow outdoors: Apr 24 to May 22Plant for fall: Jul 6 to Jul 20
Sow outdoors: Apr 24 to May 22Plant for fall: Jul 20 to Aug 3
Sow outdoors: Apr 24 to May 15
Sow outdoors: May 1 to May 29Plant for fall: Jul 20 to Aug 3
Sow outdoors: May 1 to May 22Plant for fall: Aug 3 to Aug 24
Sow outdoors: May 22 to Jun 12Plant for fall: Jul 13 to Jul 27
Sow outdoors: May 22 to Jun 5
Transplant outside: May 29 to Jun 19
Plant for fall: Sep 14 to Oct 19
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates

When to plant vegetables in Lonepine, MT

CropStart indoorsTransplantSow outdoorsFall crop
OnionsFeb 20 – Mar 6Apr 17 – May 1——
PeppersMar 6 – Mar 20May 29 – Jun 12——
EggplantMar 6 – Mar 20May 29 – Jun 12——
TomatoesMar 20 – Apr 3May 22 – Jun 5——
LettuceMar 20 – Apr 3Apr 24 – May 8Apr 17 – May 22Aug 3 – Aug 31
KaleMar 20 – Apr 3Apr 17 – May 1Apr 17 – May 1Jul 20 – Aug 10
BroccoliMar 20 – Apr 3May 1 – May 15—Jun 22 – Jul 13
CabbageMar 20 – Apr 3Apr 24 – May 8—Jun 22 – Jul 13
CauliflowerMar 20 – Apr 3May 1 – May 15—Jun 22 – Jul 13
OkraApr 3 – Apr 17Jun 5 – Jun 19Jun 5 – Jun 19—
BasilApr 3 – Apr 17May 22 – Jun 5——
Peas——Apr 3 – Apr 24Jul 6 – Jul 27
Spinach——Apr 3 – Apr 24Aug 3 – Aug 24
Radishes——Apr 10 – May 22Aug 17 – Sep 7
CucumbersApr 17 – Apr 24May 29 – Jun 5May 22 – Jun 5Jul 13 – Jul 27
Zucchini & Summer SquashApr 17 – Apr 24—May 22 – Jun 5Jul 20 – Aug 3
Winter Squash & PumpkinsApr 17 – Apr 24—May 22 – Jun 5—
Melons & WatermelonApr 17 – Apr 24May 29 – Jun 12——
Carrots——Apr 24 – May 22Jul 6 – Jul 20
Beets——Apr 24 – May 22Jul 20 – Aug 3
Potatoes——Apr 24 – May 15—
Swiss Chard——May 1 – May 29Jul 20 – Aug 3
Cilantro——May 1 – May 22Aug 3 – Aug 24
Green Beans——May 22 – Jun 12Jul 13 – Jul 27
Sweet Corn——May 22 – Jun 5—
Sweet Potatoes—May 29 – Jun 19——
Garlic———Sep 14 – Oct 19

Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.

About these dates

Based on 1991–2020 NOAA climate normals for the Skq Dam, MT weather station, 32 km away (elevation 2,730 ft (832 m)).

Frost dates near Lonepine

Frequently asked questions

When is the last frost in Lonepine, MT?

The median last spring frost in Lonepine, MT is May 15. There is still about a 10% chance of frost after June 1, so wait until then to plant frost-tender crops like tomatoes and peppers.

When is the first frost in Lonepine, MT?

The median first fall frost is September 28, with about a 10% chance of frost before September 13.

How long is the growing season in Lonepine, MT?

About 136 days between the median last spring frost and first fall frost.

What planting zone is Lonepine, MT?

Lonepine, MT is in USDA hardiness zone 6a.

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