Frost Dates & Planting Calendar for Monroe, WI

The average first fall frost in Monroe, WI is October 14, and the average last spring frost is April 27, giving a growing season of about 170 days.

Plan your garden around Monroe, WI's typical frost-free growing season, using NOAA climate normals and a 42-crop planting calendar built for this location.

Last Spring Frost

April 27

Safe May 12 Typical Apr 27 Risky Apr 12

First Fall Frost

October 14

Safe Sep 29 Typical Oct 14 Risky Oct 29

Growing Season

170 days

Typical last frost to typical first frost.

USDA Hardiness Zone

Zone 5a

A classic four-season climate with cold winters and a solid summer growing season.

Data: NOAA station MONROE WWTP, WI US, 2.3 km away.

— days until the typical last spring frost

How Monroe Compares

Monroe's typical last spring frost (Apr 27) comes earlier than in 69% of the 96 Wisconsin cities we track.
Its 170-day growing season is 8 days longer than the Wisconsin median of 162 days.
Compared with Fitchburg (42 km away), Monroe's last spring frost comes 4 days earlier than Fitchburg's, and its first fall frost arrives 5 days later.
July is the warmest month (average high 83°F) and January the coldest (average low 11°F).

Monthly Temperatures

Avg. high Avg. temp Avg. low

Planting Calendar

Vegetables
Crop	Start indoors	Direct sow	Transplant	Fall planting	Maturity	Notes
Tomato	Mar 2 – Mar 16	—	May 4 – May 11	—	60–85 days	Start indoors 6-8 weeks before last frost; transplant out 1-2 weeks after last frost once soil has warmed.
Pepper	Feb 16 – Mar 2	—	May 4 – May 18	—	60–90 days	Slow to germinate; start indoors 8-10 weeks before last frost. Transplant only once nights stay above 55F, 1-3 weeks after last frost.
Eggplant	Feb 16 – Mar 2	—	May 11 – May 18	—	65–85 days	Warm-season crop, similar timing to pepper; needs consistently warm soil (65F+) to transplant.
Cucumber	Mar 30 – Apr 6	May 4 – May 11	May 4 – May 11	—	50–65 days	Can be started indoors 3-4 weeks before transplanting, or direct-sown 1-2 weeks after last frost once soil is warm.
Zucchini	Apr 6 – Apr 13	May 4 – May 18	May 4 – May 11	—	45–55 days	Fast-growing squash; direct sow 1-3 weeks after last frost, or start indoors 2-3 weeks early for a head start.
Winter Squash	Mar 30 – Apr 6	May 4 – May 18	May 4 – May 11	—	80–110 days	Long season; direct sow after soil warms, or start indoors 3-4 weeks before last frost in short-season climates.
Pumpkin	—	May 4 – May 18	—	—	90–120 days	Direct sow 1-3 weeks after last frost; back-time from your first fall frost so the 90-120 day maturity window lands before it.
Watermelon	Mar 30 – Apr 6	—	May 11 – May 18	—	70–90 days	Needs warm soil (65F+); start indoors 3-4 weeks before last frost, transplant 2-3 weeks after last frost.
Cantaloupe	Mar 30 – Apr 6	—	May 11 – May 18	—	70–90 days	Same warm-soil requirements as watermelon; avoid disturbing roots when transplanting.
Corn	—	Apr 27 – May 11	—	—	60–100 days	Direct sow at last frost to 2 weeks after, once soil reaches 60F; does not transplant well. Succession sow every 2 weeks.
Green Bean	—	Apr 27 – May 11	—	—	50–65 days	Direct sow at last frost to 2 weeks after, once soil has warmed; frost-tender, do not rush.
Pea	—	Mar 16 – Mar 30	—	—	55–70 days	Cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked.
Lettuce	—	Mar 30 – Apr 13	—	Aug 19 – Sep 2	45–60 days	Cold-hardy; direct sow 2-4 weeks before last frost. Also transplantable from indoor starts.
Spinach	—	Mar 16 – Mar 30	—	Aug 19 – Sep 2	40–50 days	Very cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked.
Kale	—	Mar 30 – Apr 13	—	Aug 5 – Aug 19	50–65 days	Cold-hardy; direct sow 2-4 weeks before last frost or start indoors for earlier transplants.
Arugula	—	Mar 30 – Apr 13	—	Sep 2 – Sep 9	30–40 days	Fast-growing, cold-tolerant green; direct sow 2-4 weeks before last frost, succession sow every 2-3 weeks.
Swiss Chard	—	Apr 6 – Apr 20	—	—	50–60 days	Fairly cold-hardy; direct sow 1-3 weeks before last frost. Tolerates light frost in fall too.
Broccoli	Mar 9 – Mar 23	—	Apr 6 – Apr 13	Aug 12 – Aug 19	55–80 days	Start indoors 5-7 weeks before last frost; transplant out 2-3 weeks before last frost (hardens off to light frost).
Cauliflower	Mar 9 – Mar 23	—	Apr 13 – Apr 20	Aug 5 – Aug 12	55–85 days	Fussier than broccoli about temperature swings; start indoors 5-7 weeks before last frost, transplant 1-2 weeks before last frost.
Cabbage	Mar 9 – Mar 23	—	Mar 30 – Apr 13	Aug 5 – Aug 19	60–100 days	Cold-hardy; start indoors 5-7 weeks before last frost, transplant 2-4 weeks before last frost.
Brussels Sprouts	Mar 9 – Mar 23	—	Apr 6 – Apr 20	—	90–110 days	Long-season crop best timed to mature after a light fall frost for sweetest flavor; start indoors 5-7 weeks before last frost.
Carrot	—	Mar 30 – Apr 13	—	Jul 22 – Aug 5	60–80 days	Direct sow only (does not transplant); sow 2-4 weeks before last frost, as soon as soil can be worked.
Beet	—	Mar 30 – Apr 13	—	Aug 5 – Aug 19	50–65 days	Direct sow 2-4 weeks before last frost; tolerates light frost.
Radish	—	Mar 23 – Apr 6	—	Sep 2 – Sep 16	22–30 days	Very fast and cold-hardy; direct sow 3-5 weeks before last frost, as soon as soil can be worked.
Turnip	—	Mar 30 – Apr 13	—	Aug 5 – Aug 19	40–60 days	Cold-hardy; direct sow 2-4 weeks before last frost.
Onion	Feb 16 – Mar 2	—	Mar 30 – Apr 13	—	90–120 days	Start seeds indoors 8-10 weeks before last frost (or use sets/transplants); set out 2-4 weeks before last frost, very cold-tolerant as seedlings.
Garlic	—	—	—	Sep 16 – Sep 30	240–270 days	Fall-planted crop only; not planted in spring in most climates.
Potato	—	Mar 30 – Apr 13	—	—	70–120 days	Plant seed potatoes 2-4 weeks before last frost, as soon as soil can be worked and is above 45F; light frost on emerging foliage is usually tolerated.
Sweet Potato	—	—	May 11 – May 25	—	90–120 days	Set out slips 2-4 weeks after last frost once soil is thoroughly warm (65F+); very frost/cold sensitive.
Asparagus	—	—	Mar 30 – Apr 13	—	730–1095 days	Perennial; plant crowns 2-4 weeks before last frost as soon as soil can be worked. Takes 2-3 years to full production.

Herbs
Crop	Start indoors	Direct sow	Transplant	Fall planting	Maturity	Notes
Basil	Mar 16 – Mar 23	—	May 4 – May 11	—	50–70 days	Very frost/cold sensitive; start indoors 5-6 weeks before last frost, transplant only after all danger of frost (1-2 weeks after) and nights stay warm.
Cilantro	—	Apr 6 – Apr 20	—	Aug 19 – Sep 2	45–70 days	Cool-season, bolts in heat; direct sow 1-3 weeks before last frost, succession sow through spring.
Parsley	Mar 2 – Mar 16	—	Apr 13 – Apr 20	—	70–90 days	Slow to germinate; start indoors 6-8 weeks before last frost, transplant 1-2 weeks before last frost (biennial, cold-tolerant).
Dill	—	Apr 6 – Apr 20	—	—	40–60 days	Taprooted, does not transplant well; direct sow 1-3 weeks before last frost, succession sow through summer.
Oregano	Mar 2 – Mar 16	—	Apr 27 – May 4	—	80–90 days	Perennial herb; start indoors 6-8 weeks before last frost, transplant around/just after last frost date.
Thyme	Mar 2 – Mar 16	—	Apr 27 – May 4	—	85–95 days	Perennial herb, slow from seed; start indoors 6-8 weeks before last frost, transplant around/after last frost.

Flowers
Crop	Start indoors	Direct sow	Transplant	Fall planting	Maturity	Notes
Sunflower	—	May 4 – May 18	—	—	70–100 days	Direct sow 1-3 weeks after last frost once soil has warmed; taprooted, resents transplanting.
Zinnia	Mar 30 – Apr 6	May 4 – May 18	May 4 – May 11	—	60–70 days	Frost-tender; direct sow 1-3 weeks after last frost, or start indoors 3-4 weeks early for earlier blooms.
Marigold	Mar 16 – Mar 30	—	May 4 – May 11	—	45–60 days	Frost-tender; start indoors 4-6 weeks before last frost, transplant after all frost danger has passed.
Cosmos	Mar 30 – Apr 6	May 4 – May 18	May 4 – May 11	—	60–90 days	Easy from direct seed 1-3 weeks after last frost; can also start indoors 3-4 weeks early.
Nasturtium	—	May 4 – May 18	—	—	50–65 days	Frost-tender, resents root disturbance; direct sow 1-3 weeks after last frost once soil has warmed.
Dahlia	—	—	May 4 – May 18	—	90–120 days	Plant tubers 1-3 weeks after last frost once soil is warm (60F+); very frost-sensitive.

Date ranges are estimates based on university extension guidelines and this city's NOAA frost normals — not a guarantee. Scroll to see all columns on narrow screens.

Frequently Asked Questions

When is the last frost in Monroe, WI?

Based on 1991–2020 NOAA climate normals for the MONROE WWTP, WI US station, the last spring frost in Monroe typically falls around April 27. A cautious gardener might wait until May 12 (only a 10% chance of a later frost), while April 12 marks an earlier, higher-risk planting date.

When is the first frost in Monroe, WI in fall?

The first fall frost in Monroe typically arrives around October 14. To stay safe, assume frost could start as early as September 29; in milder years it can hold off until October 29.

How long is the growing season in Monroe, WI?

Monroe's average frost-free growing season is about 170 days, running from the typical last spring frost (April 27) to the typical first fall frost (October 14).

What USDA hardiness zone is Monroe, WI in?

Monroe, WI is in USDA plant hardiness zone 5a, per the USDA's 2023 Plant Hardiness Zone Map. A classic four-season climate with cold winters and a solid summer growing season.