Naperville, Illinois Weather
Fireflies rise from the lawn. Day 77 of spring. Read this microseason across nine climate regions →
Naperville weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 3Overcast——84°51°—
- ThursdayJun 4Overcast——88°59°+4°
- FridayJun 5Drizzle76%0.03″81°69°-7°
- SaturdayJun 6Light Showers67%0.76″80°63°-1°
- SundayJun 7Heavy Drizzle17%—82°69°+2°
- MondayJun 8Light Showers21%0.01″79°68°-3°
- TuesdayJun 9Light Drizzle22%—84°70°+5°
Ozone at AQI 45. AQI up 33 in the last 6 hours — air quality is degrading. Overcast through the UV peak window (cloud cover ~67%) — afternoon ozone should stay flat.
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 45. Overcast through the UV peak window (cloud cover ~67%) — afternoon ozone should stay flat.
- Present
- AQI 45
- UV peak
- 0.0 at 1 PM
- Sky at peak
- overcast
- Projected peak
- AQI 5
PM × Wind × Precip
PM2.5 at 7.1 µg/m³ (AQI 39) with a 0.87 fine-to-coarse ratio and 6 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.87
- Wind
- light
- Recent rain
- 0h in last 6h
- Pattern
- stagnant smoke
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
- 4:28 AM
- Moonset
- 1:49 PM
- In sign
- ♑︎ Capricorn
Fireflies rise from the lawn
Naperville at a glance
- Today vs. normal: 71°F — typical for the season
- Last frost: April 26 (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 — Naperville
SPC has placed Naperville in the Marginal Risk category for severe thunderstorms day after tomorrow.
- TODAYNONENo severe risk
- TOMORROWNONENo severe risk
- 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 | lettuce, peas, spinach, radishes | — |
| May | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| June | tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| July | tomatoes, peppers, beans, squash | tomatoes, beans, summer squash |
| August | — | tomatoes, beans, summer squash |
| September | fall brassicas, garlic (overwinter), carrots | tomatoes, beans, summer squash |
| October | fall brassicas, garlic (overwinter), carrots | winter squash, tomatoes (last) |
| November | — | — |
| December | — | — |
A year in weather
July brings Naperville's peak warmth with average temperatures around 74°F, while January delivers the year's coldest conditions at roughly 23°F. Precipitation follows its own calendar, with May producing the most rainfall at 4.9 inches and February offering the least at 1.8 inches.
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 23° | 1.9″ | 5 |
| February | 27° | 1.8″ | 4 |
| March | 38° | 2.4″ | 6 |
| April | 50° | 4.0″ | 8 |
| May | 61° | 4.9″ | 8 |
| June | 70° | 4.5″ | 8 |
| July | 74° | 4.2″ | 7 |
| August | 73° | 3.9″ | 7 |
| September | 66° | 3.4″ | 6 |
| October | 53° | 3.7″ | 6 |
| November | 40° | 2.7″ | 5 |
| December | 29° | 2.2″ | 5 |
Regional context
As part of the warm-summer humid continental climate region, Naperville shares temperature ranges, seasonal patterns, and growing conditions with other cities in this climate zone.
Similar climates: Chicago, IL, Rockford, IL, Round Lake Beach, IL, Aurora, IL, Joliet, IL.
Naturalist notes
Red-winged blackbirds return to Naperville's wetlands and marshes in early March, their distinctive calls marking winter's retreat.
Common lilacs typically begin blooming in mid to late May, filling neighborhoods with their characteristic purple clusters and sweet fragrance.
Frequently asked
- When does it freeze in Naperville?
- Spring's final frost usually occurs around mid-April in Naperville, while fall's first frost typically arrives around mid-November.
- What is the rainy season in Naperville?
- May produces the heaviest rainfall, averaging about 4.9 inches, while the city's total annual precipitation reaches roughly 39 inches.
- What is the warmest month in Naperville?
- July typically records the year's highest temperatures, averaging about 74°F.
- What is the coldest month in Naperville?
- January brings the coldest conditions, with temperatures averaging about 23°F.
- When can I start a vegetable garden in Naperville?
- Cool-season vegetables like peas and lettuce can go into the ground around the last spring frost in mid-April, but warm-season crops such as tomatoes and peppers should wait 1–2 weeks longer.
- How many rainy days does Naperville get?
- Naperville experiences precipitation on about 74 days each year.
- What hardiness zone is Naperville?
- Naperville's USDA hardiness zone depends on its lowest average winter temperatures; the USDA's online ZIP code lookup tool provides the current official zone designation.
Climate
Naperville, Illinois experiences a warm-summer humid continental climate. January temperatures typically hover near 23°F, while July averages 74°F, creating a 51°F seasonal swing.
Annual precipitation totals about 39 inches, distributed across roughly 74 rainy days throughout the year.
Local weather patterns emerge from the city's position at 41.7°N latitude, its proximity to large water bodies, and elevation. These factors determine what plants can grow, when frost occurs, and the daily weather patterns residents experience.