Frost Dates for Brookfield, WI 53045

Last spring frost April 27 · First fall frost October 14 · 170 frost-free days · USDA Zone 5b

Frost probability for 53045

Frost10%50%90%
Spring (last frost)May 10April 27April 13
Fall (first frost)September 30October 14October 29

Dates come from NOAA 1971–2000 freeze probabilities at the nearest reporting station (10.7 km away); the 50% date is the median year.

Frost dates by ZIP code in Brookfield, WI

ZIPLast spring frost (50%)First fall frost (50%)Zone
53045April 27October 145b
53005April 27October 145b

Month by month in Brookfield

MonthWhat to do
JanuaryPlan your garden layout and order seeds. Research varieties suited to your frost dates.
FebruaryStart peppers and eggplant indoors 8–10 weeks before your last frost (around April 27). Start tomatoes about two weeks later, 6–8 weeks before last frost.
MarchStart herbs, basil, and squash indoors (4–6 weeks before frost). Direct sow peas, spinach, and lettuce if soil is workable.
AprilLast frost around April 27. Transplant cold-hardy crops (broccoli, kale, cabbage). Harden off tomato and pepper seedlings.
MayFrost has passed. Transplant tomatoes, peppers, and basil outdoors. Direct sow beans, cucumbers, squash, and zucchini.
JuneSuccession plant lettuce and greens. Keep beds weeded and watered consistently.
JulyHarvest regularly to encourage production. Monitor for pests and disease.
AugustMidsummer: harvest beans, zucchini, cucumbers. Start brassica seeds indoors for fall.
SeptemberFirst fall frost approaching (around October 14). Transplant fall brassicas. Sow spinach, arugula, and radishes.
OctoberFirst frost around October 14. Harvest tomatoes and peppers before frost. Cover cold-hardy crops with row covers to extend the season.
NovemberHarvest remaining cold-hardy crops: kale, carrots, and beets. Plant garlic bulbs for next year.
DecemberClean up spent plants. Add compost to beds. Rest, review, and plan next year's garden.

What grows in a 170-day season

Frequently Asked Questions

What is the last frost date for Brookfield, WI (ZIP 53045)?

The median last spring frost date for Brookfield, WI (ZIP code 53045) is around April 27. This is the 50th-percentile date — meaning half of all years see frost end before this date. Use the 10% and 90% dates to understand the full range of risk in your area.

What is the first fall frost date in Brookfield, WI?

The median first fall frost date for Brookfield, WI is around October 14. Plan to harvest or protect frost-sensitive crops like tomatoes and peppers at least a week before this date to avoid losses.

How long is the growing season in Brookfield, WI?

The frost-free growing season in Brookfield is about 170 days. This window — from your last spring frost to your first fall frost — is when warm-season vegetables thrive. Cold-hardy crops like kale, spinach, and peas can extend your season by weeks on either side.

What USDA hardiness zone is Brookfield, WI?

Based on frost date patterns, Brookfield falls approximately in 5b. USDA hardiness zones are determined by average annual minimum winter temperatures and guide both plant selection and planting timing for your location.

When should I start tomatoes indoors in Brookfield, WI?

Start tomato seeds indoors 6–8 weeks before your last frost date (around April 27). For Brookfield, that's roughly March 2 to March 16. Transplant outdoors 1–2 weeks after your last frost.

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