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USDA Hardiness Zone 4b

Frost Dates for 82070 — Laramie, Wyoming

Averages from Laramie Rgnl Ap, Wy US, the nearest reporting station, 6.8 miles away.

Plant tender crops after June 2, and expect the first autumn freeze around September 15. That leaves about 102 frost-free days.

Last spring frost
June 2

50% probability

First fall frost
September 15

50% probability

Growing season
102 days

frost-free

Hardiness zone
4b

-25 to -20°F annual low

Planting calendar for 82070

What to do and when, based on the frost normals for Laramie, Wyoming
WhenWhat to do
March 24 – April 7

Start peppers and aubergines indoors

They need eight to ten weeks under lights before they can go out.

April 7 – April 21

Start tomatoes indoors

Six to eight weeks gives a transplant big enough to set fruit early.

May 5 – May 19

Sow peas, spinach, lettuce, radish outdoors

These tolerate light frost and prefer to germinate in cool soil.

June 2 onward

Transplant tomatoes, peppers, basil, squash, cucumbers

The average last freeze has passed — still watch the actual forecast.

by June 23

Sow the autumn crop of carrots, beets and brassicas

They need about twelve weeks to size up before growth stops.

by September 1

Harvest tender crops, or be ready to cover them

A first freeze two weeks early is well within normal variation.

September 15 onward

Plant garlic, mulch beds, lift tender bulbs

Garlic wants a cold spell; bare soil loses structure over winter.

What these dates mean

Wait until after June 2 to put tender plants — tomatoes, peppers, basil, squash — in the ground. That is the date by which half of years in Laramie, Wyoming are past their last freeze. Harvest before September 15, which leaves roughly 102 frost-free days.

ZIP 82070 sits in USDA hardiness zone 4b, meaning the average coldest night of the year falls between -25 to -20°F. Zone decides what survives the winter; frost dates decide when to plant each spring. They are different questions, and a plant can pass one and fail the other.

These are thirty-year NOAA averages for 1991–2020, not a forecast. Any individual year can frost two to three weeks either side of these dates, so check the actual forecast before planting out.

Other zone 4b ZIP codes in Wyoming