Greendale, Wisconsin Weather
Fireflies rise from the lawn. Day 77 of spring. Read this microseason across nine climate regions →
Greendale weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 4Overcast——85°54°—
- FridayJun 5Rain58%0.22″75°64°-10°
- SaturdayJun 6Foggy40%—83°63°+8°
- SundayJun 7Overcast——68°53°-15°
- MondayJun 8Drizzle29%0.17″68°59°0°
- TuesdayJun 9Showers33%0.48″80°63°+12°
- WednesdayJun 10Showers22%0.49″77°63°-3°
Ozone at AQI 80 now. AQI flat over the last 6 hours (within ±3 points). With UV 8.6 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 92 by mid-afternoon.
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 now. With UV 8.6 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 92 by mid-afternoon.
- Present
- AQI 80
- UV peak
- 8.6 at 1 PM
- Sky at peak
- clear
- Projected peak
- AQI 92
PM × Wind × Precip
PM2.5 at 7.8 µg/m³, PM10 at 8.3 µg/m³ — typical background levels with no transport signature.
- PM2.5/PM10
- 0.94
- 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).
A summer fog for fair, a winter fog for rain.
- Moonrise
- 4:31 AM
- Moonset
- 1:44 PM
- In sign
- ♒︎ Aquarius
Fireflies rise from the lawn
Greendale at a glance
- Today vs. normal: 10°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 4, 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 — Greendale
SPC has placed Greendale in the Marginal Risk category for severe thunderstorms tomorrow.
- TODAYTSTMGeneral Thunderstorms
- TOMORROWMRGLMarginal Risk
- DAY 3NONENo severe 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
Greendale'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
Greendale 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 Greendale?
- Greendale's last spring frost typically falls around mid-May, and the first fall frost arrives around mid-October.
- What is the rainy season in Greendale?
- 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 Greendale?
- July is typically warmest, averaging about 73°F.
- What is the coldest month in Greendale?
- January is typically coldest, averaging about 22°F.
- When can I start a vegetable garden in Greendale?
- 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 Greendale get?
- Greendale averages about 65 rainy days per year.
- What hardiness zone is Greendale?
- Greendale'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
Greendale, 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, Greendale receives about 34 inches of precipitation spread over roughly 65 rainy days.
The rhythm of the year is set by latitude (42.9°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.