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St. Joseph, MO Planting Calendar & Frost Dates

USDA hardiness zone 6a · ZIP 64501 · elevation 249′ · NOAA & USDA data

St. Joseph is in USDA hardiness zone 6a (winters can dip to -10 to -5°F), with a growing season of about 180 days between the average last spring frost (April 19) and first fall frost (October 17). The warmest month is July (avg high 88.1°F); the coldest is January (avg low 17.1°F). It averages 34.8″ of precipitation a year. Start cool-season crops several weeks before the last frost; wait until after it for tomatoes, peppers and other tender crops.

Hardiness zone
6a
min temp -10 to -5°F
Last spring frost
April 19
avg (50% prob, 32°F)
First fall frost
October 17
avg (50% prob, 32°F)
Growing season
180 days
frost-free window
Warmest month
July
avg high 88.1°F

Month-by-month typical weather in St. Joseph

Average conditions from the NOAA/NCEI 1991–2020 U.S. Climate Normals at St Joseph Rosecrans Ap, MO (4.2 mi away). Temperatures °F, precipitation & snow in inches.

MonthAvg highAvg lowMeanPrecip (in)Snow (in)
January 37.4 17.1 27.3 0.7
February 42.8 21.2 32 1
March 55.1 31.5 43.3 2.1
April 65.9 41.8 53.8 3.7
May 75.8 53.7 64.8 4.9
June 84.7 63.8 74.2 4.8
July 88.1 67.3 77.7 4.7
August 86.2 64.5 75.3 3.8
September 79.7 54.4 67 3.2
October 67.8 42.8 55.3 2.8
November 53.4 30.6 42 1.9
December 41.1 21.1 31.1 1.3

What to plant when in St. Joseph

CropSeasonWhat to do & when
TomatoeswarmStart seeds indoors: March 8 · Transplant out: April 26
PepperswarmStart seeds indoors: February 22 · Transplant out: May 3
CucumberswarmDirect sow: April 26
Zucchini / squashwarmDirect sow: April 26
Bush beanswarmDirect sow: April 26
Sweet cornwarmDirect sow: April 26
BasilwarmTransplant out: April 26
PeascoolSow (spring): March 15 · Sow (fall): August 22
SpinachcoolSow (spring): March 8 · Sow (fall): August 22
LettucecoolSow (spring): March 22 · Sow (fall): August 22
KalecoolTransplant (spring): March 29 · Sow (fall): August 8
BroccolicoolTransplant (spring): April 5
CarrotscoolSow (spring): March 29 · Sow (fall): August 8
OnionscoolTransplant (spring): March 22
PotatoescoolPlant seed potatoes: April 5
RadishescoolSow (spring): March 22 · Sow (fall): September 5

Dates are computed from St. Joseph'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 Missouri

Kansas City, MOIndependence, MOBlue Springs, MOColumbia, MOJefferson City, MOJoplin, MOSpringfield, MOSt. Peters, MO

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 Joseph Rosecrans Ap, MO, 4.2 mi (confidence: high). Monthly weather normals: St Joseph Rosecrans Ap, MO, 4.2 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.