Weather in Brookfield, Wisconsin
Roses open along the stoops. Day 59 of spring. Read this microseason across nine climate regions →
- TodayMay 17Rain64%67°52°
- MondayMay 18Heavy Rain66%76°56°
- TuesdayMay 19Showers45%71°52°
- WednesdayMay 20Overcast—55°41°
- ThursdayMay 21Overcast—57°39°
- FridayMay 22Overcast10%61°46°
- SaturdayMay 23Overcast10%66°53°
- PM 2.5
- 18.6 μg/m³
- PM 10
- 19.7 μg/m³
- NO₂
- 31.6 μg/m³
- Ozone
- 60.0 μg/m³
- UV Index
- 0.0 Low
When the dew is on the grass, rain will never come to pass.
- Moonrise
- 10:29 AM
- Moonset
- 1:43 AM
- In sign
- ♊︎ Gemini
Roses open along the stoops
Brookfield at a glance
- Today vs. normal: 3°F below the seasonal normal for this latitude
- Last frost: May 4 (climatological average for this latitude)
- Microseason: 28 of 72, May 16–20
- Planting window: Direct sow okra, melons, and southern peas. Thin carrot rows.
Right now in the garden
Cool-season window is open
As of May 17, the cool-season window is open or about to open. Direct-sow peas, lettuce, spinach, radishes, and brassicas now. Hold off on warm-season crops until 1–2 weeks after the last spring frost (around May).
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.