Brookfield, Wisconsin Weather
Fireflies rise from the lawn. Day 76 of spring. Read this microseason across nine climate regions →
Brookfield weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 3Overcast——81°47°—
- ThursdayJun 4Overcast——85°57°+4°
- FridayJun 5Light Showers81%0.33″73°66°-12°
- SaturdayJun 6Heavy Showers63%0.50″77°59°+4°
- SundayJun 7Foggy——74°54°-3°
- MondayJun 8Light Drizzle15%—77°57°+3°
- TuesdayJun 9Light Drizzle16%—78°66°+1°
Ozone at AQI 80 — peak already passed at 1 PM under clear skies. AQI up 12 over the last 6 hours (gradual rise). Levels should ease through evening.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion.
What's driving it
Ozone × UV × Sky
Ozone at AQI 80 — peak already passed at 1 PM under clear skies. Levels should ease through evening.
- Present
- AQI 80
- UV peak
- 3.6 at earlier today
- Sky at peak
- clear
- Projected peak
- AQI 80
PM × Wind × Precip
PM2.5 at 7.7 µg/m³, PM10 at 8.4 µg/m³ — typical background levels with no transport signature.
- PM2.5/PM10
- 0.92
- Wind
- breezy
- Recent rain
- 0h in last 6h
- Pattern
- background
Trends
Seven days of AQI and PM2.5.
Hourly air-quality data from the Copernicus Atmosphere Monitoring Service, charted across the past and next several days. Dashed lines mark the AQI breakpoints at 50 (Good → Moderate) and 100 (Moderate → Unhealthy for Sensitive Groups).
The higher the clouds, the finer the weather.
- Moonrise
- 3:56 AM
- Moonset
- 12:39 PM
- In sign
- ♑︎ Capricorn
Fireflies rise from the lawn
Brookfield at a glance
- Today vs. normal: 8°F above the seasonal normal for this latitude
- Last frost: May 4 (climatological average for this latitude)
- Microseason: Jun 1–5
- Planting window: Harvest spring lettuce before it bolts. Sow heat-tolerant greens.
Right now in the garden
Peak growing season
As of June 3, the growing season is at its peak — frost is months away. Continue succession-planting beans and summer squash. Start fall brassicas (broccoli, cabbage, kale) from seed indoors for transplanting in late summer.
SPC Convective Outlook
Storm Prediction Center — Brookfield
SPC has placed Brookfield in the Marginal Risk category for severe thunderstorms day after tomorrow.
- TODAYNONENo severe risk
- TOMORROWTSTMGeneral Thunderstorms
- DAY 3MRGLMarginal Risk
Isolated severe storms possible. Limited threat for hail or damaging wind.
Source: NOAA / NWS Storm Prediction Center categorical convective outlook. Outlooks are re-issued multiple times per day; this page reflects the most recent SPC polygons covering the city’s coordinates.
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| January | — | — |
| February | — | — |
| March | — | — |
| April | — | — |
| May | lettuce, peas, spinach, radishes | lettuce, peas, radishes |
| June | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| July | tomatoes, peppers, beans, squash | tomatoes, beans, summer squash |
| August | tomatoes, peppers, beans, squash, fall brassicas, garlic (overwinter), carrots | tomatoes, beans, summer squash |
| September | fall brassicas, garlic (overwinter), carrots | tomatoes, beans, summer squash |
| October | — | winter squash, tomatoes (last) |
| November | — | — |
| December | — | — |
A year in weather
Brookfield's warmest month is July (~73°F mean) and its coldest is January (~22°F). Rainfall peaks in June (4.8 inches) and bottoms out in January (1.5 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 22° | 1.5″ | 4 |
| February | 25° | 1.5″ | 4 |
| March | 35° | 1.8″ | 4 |
| April | 46° | 3.7″ | 7 |
| May | 58° | 3.7″ | 8 |
| June | 68° | 4.8″ | 7 |
| July | 73° | 3.6″ | 6 |
| August | 71° | 3.7″ | 6 |
| September | 64° | 3.0″ | 6 |
| October | 51° | 2.7″ | 5 |
| November | 39° | 2.0″ | 5 |
| December | 28° | 1.7″ | 5 |
Regional context
Brookfield sits within a warm-summer humid continental climate region — a cohort that shares similar temperature ranges, seasonal patterns, and growing conditions across nearby cities.
Similar climates: Milwaukee, WI, Madison, WI, Appleton, WI, Green Bay, WI, Racine, WI.
Frequently asked
- When does it freeze in Brookfield?
- Brookfield's last spring frost typically falls around mid-May, and the first fall frost arrives around mid-October.
- What is the rainy season in Brookfield?
- June is the wettest month with about 4.8 inches of rain on average; the city receives roughly 34 inches annually.
- What is the warmest month in Brookfield?
- July is typically warmest, averaging about 73°F.
- What is the coldest month in Brookfield?
- January is typically coldest, averaging about 22°F.
- When can I start a vegetable garden in Brookfield?
- Cool-season crops (peas, lettuce) can be sown around the last spring frost (mid-May); warm-season crops (tomatoes, peppers) wait until 1–2 weeks after.
- How many rainy days does Brookfield get?
- Brookfield averages about 65 rainy days per year.
- What hardiness zone is Brookfield?
- Brookfield's USDA hardiness zone is determined by its lowest average winter temperature; check the USDA's online lookup with the city ZIP for the current zone designation.
Climate
Brookfield, Wisconsin sits in a warm-summer humid continental climate zone. January means hover near 22°F while July averages 73°F — a 51°F seasonal swing.
Across the year, Brookfield receives about 34 inches of precipitation spread over roughly 65 rainy days.
The rhythm of the year is set by latitude (43.1°N), proximity to large water bodies, and elevation — all of which shape what grows here, when frost is likely, and what the weather story looks like day to day.