Weather in Naperville, Illinois
Roses open along the stoops. Day 59 of spring. Read this microseason across nine climate regions →
When the dew is on the grass, rain will never come to pass.
- Moonrise
- 10:35 AM
- Moonset
- 1:38 AM
- In sign
- ♉︎ Taurus
Roses open along the stoops
Naperville at a glance
- Today vs. normal: NaN°F below the seasonal normal for this latitude
- Last frost: April 26 (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
Warm-season window is open
As of May 17, the last spring frost has passed for most years. Transplant tomatoes, peppers, eggplants, basil, and cucurbits (cucumbers, squash, melons) now. Direct-sow beans and corn into warm soil.
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.