Rochelle, Illinois Weather
Fireflies rise from the lawn. Day 76 of spring. Read this microseason across nine climate regions →
Rochelle weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 3Overcast——83°49°—
- ThursdayJun 4Overcast——87°57°+4°
- FridayJun 5Showers75%0.35″77°67°-10°
- SaturdayJun 6Showers66%0.05″82°64°+5°
- SundayJun 7Overcast22%—80°61°-2°
- MondayJun 8Light Drizzle27%0.01″77°66°-3°
- TuesdayJun 9Drizzle23%0.01″79°69°+2°
Ozone at AQI 65 — peak already passed at 1 PM under clear skies. AQI up 22 in the last 6 hours — air quality is degrading. 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 65 — peak already passed at 1 PM under clear skies. Levels should ease through evening.
- Present
- AQI 65
- UV peak
- 2.0 at earlier today
- Sky at peak
- clear
- Projected peak
- AQI 65
PM × Wind × Precip
PM2.5 at 5.1 µg/m³ (AQI 28) with a 0.78 fine-to-coarse ratio and 5 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.78
- 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).
The higher the clouds, the finer the weather.
- Moonrise
- 3:55 AM
- Moonset
- 12:47 PM
- In sign
- ♑︎ Capricorn
Fireflies rise from the lawn
Rochelle at a glance
- Today vs. normal: 10°F above the seasonal normal for this latitude
- Last frost: April 28 (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 — Rochelle
SPC has placed Rochelle 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
Rochelle's warmest month is July (~72°F mean) and its coldest is January (~20°F). Rainfall peaks in June (4.9 inches) and bottoms out in February (1.7 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 20° | 1.8″ | 4 |
| February | 24° | 1.7″ | 5 |
| March | 36° | 2.3″ | 5 |
| April | 48° | 3.4″ | 7 |
| May | 59° | 4.7″ | 9 |
| June | 69° | 4.9″ | 8 |
| July | 72° | 3.5″ | 6 |
| August | 70° | 3.9″ | 6 |
| September | 63° | 3.3″ | 6 |
| October | 51° | 2.8″ | 6 |
| November | 38° | 2.3″ | 5 |
| December | 26° | 1.9″ | 5 |
Regional context
Rochelle's baseline climate, derived from NOAA NCEI 1991-2020 normals at the nearest reporting station, swings from a January mean of 20°F to a July mean of 72°F — a 52°F seasonal arc typical of the mid-latitude bands. Annual precipitation runs about 36.6 inches spread across roughly 71 days with measurable rain or snow each year.
Precipitation runs summer-dominant here: June averages 4.9 inches across 7.7 days with measurable rain, driven mostly by warm-season storms and thunderstorm activity, while February drops to just 1.7 inches across 4.5 rainy days under drier cool-season air. That wet-warm-summer pattern groups Rochelle with places like Hillcrest, IL, Creston, IL and Steward, IL — a regional cohort where summer thunderstorm season carries more than half the annual moisture.
The frost-sensitive growing window opens around mid-April, when overnight lows reliably clear freezing for cool-season crops like kale, peas, spinach, and parsnips. Warm-season transplants — tomatoes, peppers, and basil — typically wait two weeks past that date to avoid late spring cold snaps. The window closes around mid-November, when overnight lows resume dipping below freezing and frost-tender plants need protection or harvest. These are 30-year central tendencies; year-to-year frost dates can move by up to two weeks. Local features matter: a south-facing slope inside Rochelle typically runs 3-5 days ahead of the regional last-frost date, while a low-lying lot along a creek or drainage can lag the same date by a week or more on calm clear nights.
Similar climates: Hillcrest, IL, Creston, IL, Steward, IL, Kings, IL, Ashton, IL.
Frequently asked
- When does it freeze in Rochelle?
- Rochelle's last spring frost typically falls around mid-April, and the first fall frost arrives around mid-November.
- What is the rainy season in Rochelle?
- June is the wettest month with about 4.9 inches of rain on average; the city receives roughly 37 inches annually.
- What is the warmest month in Rochelle?
- July is typically warmest, averaging about 72°F.
- What is the coldest month in Rochelle?
- January is typically coldest, averaging about 20°F.
- When can I start a vegetable garden in Rochelle?
- Cool-season crops (peas, lettuce) can be sown around the last spring frost (mid-April); warm-season crops (tomatoes, peppers) wait until 1–2 weeks after.
- How many rainy days does Rochelle get?
- Rochelle averages about 71 rainy days per year.
- What hardiness zone is Rochelle?
- Rochelle'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
Rochelle, Illinois sits in a warm-summer humid continental climate zone. January means hover near 20°F while July averages 72°F — a 52°F seasonal swing.
Across the year, Rochelle receives about 37 inches of precipitation spread over roughly 71 rainy days.
The rhythm of the year is set by latitude (41.9°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.