When is the last frost in St. George, UT?

The average last spring frost (50% probability of 32°F) in St. George is around March 14, based on NOAA/NCEI 1991–2020 normals at the St George, UT station (1.8 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 St. George?

The average first fall frost in St. George, UT is around November 10, giving roughly a 239-day frost-free growing season.

What planting zone is St. George, UT?

St. George is in USDA plant hardiness zone 8b (average annual extreme minimum temperature 15 to 20°F), from the 2023 USDA Plant Hardiness Zone Map.

What is the weather like in St. George?

In St. George, UT the warmest month is July (avg high 101.9°F) and the coldest is December (avg low 27.9°F). It averages about 9.3″ of precipitation a year and 1.2″ of snow.

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St. George, UT Planting Calendar & Frost Dates

USDA hardiness zone 8b · ZIP 84770 · elevation 871′ · NOAA & USDA data

St. George is in USDA hardiness zone 8b (winters can dip to 15 to 20°F), with a growing season of about 239 days between the average last spring frost (March 14) and first fall frost (November 10). The warmest month is July (avg high 101.9°F); the coldest is December (avg low 27.9°F). It averages 9.3″ of precipitation a year and 1.2″ 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 15 to 20°F

Last spring frost

March 14

avg (50% prob, 32°F)

First fall frost

November 10

avg (50% prob, 32°F)

Growing season

239 days

frost-free window

Warmest month

July

avg high 101.9°F

Month-by-month typical weather in St. George

Average conditions from the NOAA/NCEI 1991–2020 U.S. Climate Normals at St George, UT (1.8 mi away). Temperatures °F, precipitation & snow in inches.

Month	Avg high	Avg low	Mean	Precip (in)	Snow (in)
January	54	28.4	41.2	1.2	0.5
February	59.3	32.4	45.8	1.4	0.5
March	67.8	39	53.4	1	0.2
April	75	45.7	60.4	0.7	0
May	85.4	55.5	70.5	0.3	0
June	96.4	64.5	80.4	0.2	0
July	101.9	71.7	86.8	0.5	0
August	99.9	70.3	85.1	1.1	0
September	92.4	60.7	76.5	0.7	0
October	78.8	47.3	63	0.8	0
November	63.8	34.7	49.2	0.7	0
December	53	27.9	40.4	0.9	0

What to plant when in St. George

Crop	Season	What to do & when
Tomatoes	warm	Start seeds indoors: January 31 · Transplant out: March 21
Peppers	warm	Start seeds indoors: January 17 · Transplant out: March 28
Cucumbers	warm	Direct sow: March 21
Zucchini / squash	warm	Direct sow: March 21
Bush beans	warm	Direct sow: March 21
Sweet corn	warm	Direct sow: March 21
Basil	warm	Transplant out: March 21
Peas	cool	Sow (spring): February 7 · Sow (fall): September 15
Spinach	cool	Sow (spring): January 31 · Sow (fall): September 15
Lettuce	cool	Sow (spring): February 14 · Sow (fall): September 15
Kale	cool	Transplant (spring): February 21 · Sow (fall): September 1
Broccoli	cool	Transplant (spring): February 28
Carrots	cool	Sow (spring): February 21 · Sow (fall): September 1
Onions	cool	Transplant (spring): February 14
Potatoes	cool	Plant seed potatoes: February 28
Radishes	cool	Sow (spring): February 14 · Sow (fall): September 29

Dates are computed from St. George'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 Utah

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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 — St George, UT, 1.8 mi (confidence: high). Monthly weather normals: St George, UT, 1.8 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.