Laramie, WY planting zone & frost dates

Laramie is in USDA hardiness zone 4a. The last spring frost usually comes around June 7 and the first fall frost around September 4, for a growing season of about 88 days.

USDA hardiness zone4aavg. extreme winter low -30°F to -25°F
Average last spring frostJune 790% chance of no frost after June 29
Average first fall frostSeptember 410% chance of frost by August 17
Growing season88 daysfrost-free days in an average year

Planting calendar for Laramie

Dates are counted from the average last spring frost (June 7) using the typical timing recommended by U.S. extension services. Warm-season crops go out only after the danger of frost has passed and the soil has warmed.

CropWhen
TomatoesStart seeds indoors: Apr 12 – Apr 26
Transplant outdoors: Jun 14 – Jun 21
PeppersStart seeds indoors: Mar 29 – Apr 12
Transplant outdoors: Jun 21 – Jun 28
EggplantStart seeds indoors: Mar 29 – Apr 12
Transplant outdoors: Jun 21 – Jun 28
BroccoliStart seeds indoors: Mar 29 – Apr 12
Transplant outdoors: May 10 – May 24
CabbageStart seeds indoors: Mar 29 – Apr 12
Transplant outdoors: May 10 – May 24
Onions (sets)Plant outdoors: May 10 – May 24
PeasSow outdoors: Apr 26 – May 10
SpinachSow outdoors: Apr 26 – May 10
LettuceSow outdoors: May 10 – May 24
CarrotsSow outdoors: May 10 – May 24
PotatoesPlant outdoors: May 10 – May 24
BeansSow outdoors: Jun 14 – Jun 21
Sweet cornSow outdoors: Jun 14 – Jun 21
CucumbersSow outdoors: Jun 14 – Jun 21
Squash & zucchiniSow outdoors: Jun 14 – Jun 21
BasilStart seeds indoors: Apr 26 – May 10
Transplant outdoors: Jun 14 – Jun 21

Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Jul 10 (8 weeks before the average first fall frost on Sep 4).

Useful for zone 4a gardens

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Frost risk in detail

90% chance50% chance10% chance
Last 32°F frost in spring is afterMay 23Jun 7Jun 29
First 32°F frost in fall is beforeSep 18Sep 4Aug 17

How to read it: in spring there is a 10% chance of a frost after June 29, so that is a safe date for tender plants. In fall there is a 10% chance of frost before August 17. A hard freeze (28°F) usually ends around May 22.

Hardiness zone by ZIP code in Laramie

Nearby cities

All cities in Wyoming → · Other zone 4a cities →

Questions

What growing zone is Laramie, WY?

Laramie is in USDA Plant Hardiness Zone 4a (average extreme winter low -30°F to -25°F), according to the USDA 2023 map. Some ZIP codes of the city fall in zones 4b, 5b.

When is the last frost in Laramie?

The average last spring frost (32°F) in Laramie is June 7. There is still a 10% chance of frost until June 29.

When can I plant tomatoes in Laramie?

Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Jun 14 – Jun 21. Start seeds indoors 6–8 weeks before the last frost.

Frost dates: NOAA U.S. Climate Normals 1991–2020, station Laramie 2 Nw, WY (USC00485435), 3.4 km (2.1 mi) from the city center, elevation 2176 m, based on 18 years of records. Hardiness zone: USDA Plant Hardiness Zone Map 2023 for the ZIP code nearest to the city center. Microclimates (valleys, hills, cities, coasts) can be warmer or colder: check the local forecast before planting. How we calculate the data.