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Chesterfield, MO Planting Calendar & Frost Dates

USDA hardiness zone 6b · ZIP 63005 · elevation 186′ · NOAA & USDA data

Chesterfield is in USDA hardiness zone 6b (winters can dip to -5 to 0°F), with a growing season of about 193 days between the average last spring frost (April 12) and first fall frost (October 23). The warmest month is July (avg high 87.5°F); the coldest is January (avg low 21.2°F). It averages 44.4″ of precipitation a year and 13.5″ 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
6b
min temp -5 to 0°F
Last spring frost
April 12
avg (50% prob, 32°F)
First fall frost
October 23
avg (50% prob, 32°F)
Growing season
193 days
frost-free window
Warmest month
July
avg high 87.5°F

Month-by-month typical weather in Chesterfield

Average conditions from the NOAA/NCEI 1991–2020 U.S. Climate Normals at Weldon Spring Nws, MO (4.1 mi away). Temperatures °F, precipitation & snow in inches.

MonthAvg highAvg lowMeanPrecip (in)Snow (in)
January 39.3 21.2 30.3 2.6 4.1
February 44.8 24.4 34.6 2.4 3.7
March 55.2 33.3 44.2 3.7 1.7
April 67 43.8 55.4 4.7 0.2
May 75.7 54.2 65 5.1 0
June 83.7 63.3 73.5 4.7 0
July 87.5 67.3 77.4 3.9 0
August 86.7 65.4 76 3.6 0
September 79.8 57 68.4 3.5 0
October 68.3 45.6 56.9 3.4 0
November 55.4 34.9 45.2 3.7 0.8
December 44 25.9 35 3.1 3

What to plant when in Chesterfield

CropSeasonWhat to do & when
TomatoeswarmStart seeds indoors: March 1 · Transplant out: April 19
PepperswarmStart seeds indoors: February 15 · Transplant out: April 26
CucumberswarmDirect sow: April 19
Zucchini / squashwarmDirect sow: April 19
Bush beanswarmDirect sow: April 19
Sweet cornwarmDirect sow: April 19
BasilwarmTransplant out: April 19
PeascoolSow (spring): March 8 · Sow (fall): August 28
SpinachcoolSow (spring): March 1 · Sow (fall): August 28
LettucecoolSow (spring): March 15 · Sow (fall): August 28
KalecoolTransplant (spring): March 22 · Sow (fall): August 14
BroccolicoolTransplant (spring): March 29
CarrotscoolSow (spring): March 22 · Sow (fall): August 14
OnionscoolTransplant (spring): March 15
PotatoescoolPlant seed potatoes: March 29
RadishescoolSow (spring): March 15 · Sow (fall): September 11

Dates are computed from Chesterfield'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

St. Peters, MOSt. Charles, MOFlorissant, MOSt. Louis, MOJefferson City, MOColumbia, MOCape Girardeau, MOSpringfield, 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 Louis Sprt Of S L Ap, MO, 0.9 mi (confidence: high). Monthly weather normals: Weldon Spring Nws, MO, 4.1 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.