When is the last frost in Dubuque, IA?

The average last spring frost (50% probability of 32°F) in Dubuque is around April 19, based on NOAA/NCEI 1991–2020 normals at the Dubuque L&d 11, IA station (2.5 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 Dubuque?

The average first fall frost in Dubuque, IA is around October 21, giving roughly a 184-day frost-free growing season.

What planting zone is Dubuque, IA?

Dubuque 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 Dubuque?

In Dubuque, IA the warmest month is July (avg high 84.5°F) and the coldest is January (avg low 10.1°F). It averages about 38.8″ of precipitation a year and 36.1″ of snow.

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Dubuque, IA Planting Calendar & Frost Dates

USDA hardiness zone 5a · ZIP 52001 · elevation 189′ · NOAA & USDA data

Dubuque is in USDA hardiness zone 5a (winters can dip to -20 to -15°F), with a growing season of about 184 days between the average last spring frost (April 19) and first fall frost (October 21). The warmest month is July (avg high 84.5°F); the coldest is January (avg low 10.1°F). It averages 38.8″ of precipitation a year and 36.1″ 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

April 19

avg (50% prob, 32°F)

First fall frost

October 21

avg (50% prob, 32°F)

Growing season

184 days

frost-free window

Warmest month

July

avg high 84.5°F

Month-by-month typical weather in Dubuque

Average conditions from the NOAA/NCEI 1991–2020 U.S. Climate Normals at Dubuque L&d 11, IA (2.5 mi away). Temperatures °F, precipitation & snow in inches.

Month	Avg high	Avg low	Mean	Precip (in)	Snow (in)
January	27.5	10.1	18.8	1.3	11.7
February	32.2	13.1	22.6	1.4	8.6
March	44.7	25.4	35	2.1	3.7
April	58.5	37.5	48	3.8	0.9
May	70.9	49.3	60.1	4.4	0
June	80.9	59.9	70.4	5.6	0
July	84.5	64.2	74.3	5.3	0
August	82.1	62.3	72.2	3.8	0
September	75	54	64.5	3.9	0
October	61.4	41.7	51.6	3.1	0.1
November	45.7	29.2	37.5	2.4	1.2
December	32.9	17.7	25.3	1.7	9.9

What to plant when in Dubuque

Crop	Season	What to do & when
Tomatoes	warm	Start seeds indoors: March 8 · Transplant out: April 26
Peppers	warm	Start seeds indoors: February 22 · Transplant out: May 3
Cucumbers	warm	Direct sow: April 26
Zucchini / squash	warm	Direct sow: April 26
Bush beans	warm	Direct sow: April 26
Sweet corn	warm	Direct sow: April 26
Basil	warm	Transplant out: April 26
Peas	cool	Sow (spring): March 15 · Sow (fall): August 26
Spinach	cool	Sow (spring): March 8 · Sow (fall): August 26
Lettuce	cool	Sow (spring): March 22 · Sow (fall): August 26
Kale	cool	Transplant (spring): March 29 · Sow (fall): August 12
Broccoli	cool	Transplant (spring): April 5
Carrots	cool	Sow (spring): March 29 · Sow (fall): August 12
Onions	cool	Transplant (spring): March 22
Potatoes	cool	Plant seed potatoes: April 5
Radishes	cool	Sow (spring): March 22 · Sow (fall): September 9

Dates are computed from Dubuque'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 Iowa

Cedar Rapids, IA Davenport, IA Iowa City, IA Waterloo, IA Cedar Falls, IA Ames, IA Ankeny, IA Des Moines, IA

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 — Dubuque L&d 11, IA, 2.5 mi (confidence: high). Monthly weather normals: Dubuque L&d 11, IA, 2.5 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.