When is the last frost in Royal Oak, MI?

The average last spring frost (50% probability of 32°F) in Royal Oak is around April 21, based on NOAA/NCEI 1991–2020 normals at the Detroit City Ap, MI station (8.6 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 Royal Oak?

The average first fall frost in Royal Oak, MI is around October 31, giving roughly a 190-day frost-free growing season.

What planting zone is Royal Oak, MI?

Royal Oak is in USDA plant hardiness zone 6b (average annual extreme minimum temperature -5 to 0°F), from the 2023 USDA Plant Hardiness Zone Map.

What is the weather like in Royal Oak?

In Royal Oak, MI the warmest month is July (avg high 82.9°F) and the coldest is January (avg low 15.6°F). It averages about 33″ of precipitation a year and 36″ of snow.

Home › Michigan › Royal Oak

Royal Oak, MI Planting Calendar & Frost Dates

USDA hardiness zone 6b · ZIP 48067 · elevation 220′ · NOAA & USDA data

Royal Oak is in USDA hardiness zone 6b (winters can dip to -5 to 0°F), with a growing season of about 190 days between the average last spring frost (April 21) and first fall frost (October 31). The warmest month is July (avg high 82.9°F); the coldest is January (avg low 15.6°F). It averages 33″ of precipitation a year and 36″ 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 -5 to 0°F

Last spring frost

April 21

avg (50% prob, 32°F)

First fall frost

October 31

avg (50% prob, 32°F)

Growing season

190 days

frost-free window

Warmest month

July

avg high 82.9°F

Month-by-month typical weather in Royal Oak

Average conditions from the NOAA/NCEI 1991–2020 U.S. Climate Normals at Farmington, MI (11.6 mi away). Temperatures °F, precipitation & snow in inches.

Month	Avg high	Avg low	Mean	Precip (in)	Snow (in)
January	30.4	15.6	23	2.3	9.8
February	33.7	15.7	24.7	1.8	10.6
March	43.6	24	33.8	2.1	4.7
April	56.7	34.1	45.4	3.1	1.5
May	68.5	45.8	57.1	3.6	0
June	78.4	56	67.2	3.3	0
July	82.9	59.8	71.4	3.2	0
August	80.7	58.9	69.8	3.2	0
September	73.5	51	62.2	3.4	0
October	60.3	39.9	50.1	2.7	0
November	46.7	29.7	38.2	2.5	2.3
December	35.4	21.8	28.6	2	7.1

What to plant when in Royal Oak

Crop	Season	What to do & when
Tomatoes	warm	Start seeds indoors: March 10 · Transplant out: April 28
Peppers	warm	Start seeds indoors: February 24 · Transplant out: May 5
Cucumbers	warm	Direct sow: April 28
Zucchini / squash	warm	Direct sow: April 28
Bush beans	warm	Direct sow: April 28
Sweet corn	warm	Direct sow: April 28
Basil	warm	Transplant out: April 28
Peas	cool	Sow (spring): March 17 · Sow (fall): September 5
Spinach	cool	Sow (spring): March 10 · Sow (fall): September 5
Lettuce	cool	Sow (spring): March 24 · Sow (fall): September 5
Kale	cool	Transplant (spring): March 31 · Sow (fall): August 22
Broccoli	cool	Transplant (spring): April 7
Carrots	cool	Sow (spring): March 31 · Sow (fall): August 22
Onions	cool	Transplant (spring): March 24
Potatoes	cool	Plant seed potatoes: April 7
Radishes	cool	Sow (spring): March 24 · Sow (fall): September 19

Dates are computed from Royal Oak'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 Michigan

Troy, MI Sterling Heights, MI Southfield, MI Warren, MI Roseville, MI Detroit, MI St. Clair Shores, MI Dearborn, MI

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 — Detroit City Ap, MI, 8.6 mi (confidence: high). Monthly weather normals: Farmington, MI, 11.6 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.