When is the last frost in Greeley, CO?

The average last spring frost (50% probability of 32°F) in Greeley is around May 2, based on NOAA/NCEI 1991–2020 normals at the Greeley Unc, CO station (3.1 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 Greeley?

The average first fall frost in Greeley, CO is around October 8, giving roughly a 159-day frost-free growing season.

What planting zone is Greeley, CO?

Greeley 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 Greeley?

In Greeley, CO the warmest month is July (avg high 91.7°F) and the coldest is January (avg low 17.5°F). It averages about 14.7″ of precipitation a year and 34.9″ of snow.

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Greeley, CO Planting Calendar & Frost Dates

USDA hardiness zone 5a · ZIP 80631 · elevation 1437′ · NOAA & USDA data

Greeley is in USDA hardiness zone 5a (winters can dip to -20 to -15°F), with a growing season of about 159 days between the average last spring frost (May 2) and first fall frost (October 8). The warmest month is July (avg high 91.7°F); the coldest is January (avg low 17.5°F). It averages 14.7″ of precipitation a year and 34.9″ 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 2

avg (50% prob, 32°F)

First fall frost

October 8

avg (50% prob, 32°F)

Growing season

159 days

frost-free window

Warmest month

July

avg high 91.7°F

Month-by-month typical weather in Greeley

Average conditions from the NOAA/NCEI 1991–2020 U.S. Climate Normals at Greeley Unc, CO (3.1 mi away). Temperatures °F, precipitation & snow in inches.

Month	Avg high	Avg low	Mean	Precip (in)	Snow (in)
January	44.1	17.5	30.8	0.5	5.7
February	47.7	20	33.9	0.5	5.1
March	59.1	28.1	43.6	0.9	5.1
April	66	35.3	50.7	1.8	3.7
May	74.7	44.5	59.6	2.7	0.5
June	85.8	53.6	69.7	1.8	0
July	91.7	59.3	75.5	1.6	0
August	89.2	57.3	73.3	1.6	0
September	81.9	48.7	65.3	1.1	0.5
October	67.8	36.6	52.2	1.1	3.3
November	53.6	25.8	39.7	0.7	5.4
December	43.4	17.8	30.6	0.6	5.6

What to plant when in Greeley

Crop	Season	What to do & when
Tomatoes	warm	Start seeds indoors: March 21 · Transplant out: May 9
Peppers	warm	Start seeds indoors: March 7 · Transplant out: May 16
Cucumbers	warm	Direct sow: May 9
Zucchini / squash	warm	Direct sow: May 9
Bush beans	warm	Direct sow: May 9
Sweet corn	warm	Direct sow: May 9
Basil	warm	Transplant out: May 9
Peas	cool	Sow (spring): March 28 · Sow (fall): August 13
Spinach	cool	Sow (spring): March 21 · Sow (fall): August 13
Lettuce	cool	Sow (spring): April 4 · Sow (fall): August 13
Kale	cool	Transplant (spring): April 11 · Sow (fall): July 30
Broccoli	cool	Transplant (spring): April 18
Carrots	cool	Sow (spring): April 11 · Sow (fall): July 30
Onions	cool	Transplant (spring): April 4
Potatoes	cool	Plant seed potatoes: April 18
Radishes	cool	Sow (spring): April 4 · Sow (fall): August 27

Dates are computed from Greeley'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 Colorado

Fort Collins, CO Loveland, CO Longmont, CO Thornton, CO Boulder, CO Commerce City, CO Broomfield, CO Westminster, CO

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 — Greeley Unc, CO, 3.1 mi (confidence: high). Monthly weather normals: Greeley Unc, CO, 3.1 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.