Pecatonica, Illinois Weather
Fireflies rise from the lawn. Day 77 of spring. Read this microseason across nine climate regions →
Pecatonica weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 3Overcast——82°47°—
- ThursdayJun 4Overcast——85°58°+3°
- FridayJun 5Heavy Showers73%0.17″79°68°-6°
- SaturdayJun 6Heavy Showers68%0.50″85°66°+6°
- SundayJun 7Heavy Drizzle17%—80°66°-5°
- MondayJun 8Light Showers29%—78°63°-2°
- TuesdayJun 9Light Drizzle23%—85°69°+7°
PM2.5 at 7.9 µg/m³, PM10 at 9.4 µg/m³ — typical background levels with no transport signature. AQI up 19 in the last 6 hours — air quality is degrading.
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 36. Overcast through the UV peak window (cloud cover ~100%) — afternoon ozone should stay flat.
- Present
- AQI 36
- UV peak
- 0.0 at 1 PM
- Sky at peak
- overcast
- Projected peak
- AQI 4
PM × Wind × Precip
PM2.5 at 7.9 µg/m³, PM10 at 9.4 µg/m³ — typical background levels with no transport signature.
- PM2.5/PM10
- 0.84
- Wind
- light
- 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
- 4:35 AM
- Moonset
- 1:52 PM
- In sign
- ♑︎ Capricorn
Fireflies rise from the lawn
Pecatonica at a glance
- Today vs. normal: 5°F below the seasonal normal for this latitude
- Last frost: April 30 (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 — Pecatonica
SPC has placed Pecatonica in the Marginal Risk category for severe thunderstorms day after tomorrow.
- TODAYNONENo severe risk
- TOMORROWTSTMGeneral Thunderstorms
- 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 | — | — |
| 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
Pecatonica's warmest month is July (~72°F mean) and its coldest is January (~20°F). Rainfall peaks in June (5.3 inches) and bottoms out in January (1.6 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 20° | 1.6″ | 4 |
| February | 24° | 1.6″ | 4 |
| March | 35° | 2.1″ | 5 |
| April | 47° | 3.7″ | 7 |
| May | 59° | 4.4″ | 8 |
| June | 69° | 5.3″ | 8 |
| July | 72° | 4.2″ | 6 |
| August | 70° | 4.2″ | 6 |
| September | 63° | 4.1″ | 6 |
| October | 50° | 3.0″ | 5 |
| November | 37° | 2.4″ | 5 |
| December | 26° | 1.8″ | 5 |
Regional context
Pecatonica's climate, per the NOAA NCEI 1991-2020 normals from the nearest reporting station, runs cold-winter and warm-summer. January means hover near 20°F while July climbs to 72°F — a 53°F seasonal swing typical of northern-tier latitudes. Annual precipitation totals about 38.4 inches spread across roughly 69 days with measurable rain or snow.
Precipitation runs summer-dominant here: June averages 5.3 inches across 8.0 days with measurable rain, driven mostly by warm-season storms and thunderstorm activity, while January drops to just 1.6 inches across 4.4 rainy days under drier cool-season air. That summer-storm-driven distribution puts Pecatonica in a cohort with places like Westlake Village, IL, Ridott, IL and Winnebago, IL, all of which depend on warm-season convective activity for the bulk of their annual moisture.
The frost-sensitive growing window opens around late-May, when overnight lows reliably clear freezing for cool-season crops like kale, peas, spinach, and parsnips. Warm-soil crops — tomatoes, peppers, eggplant — wait until soil temperatures reach the mid-50s°F, usually two weeks past the last-frost date. The window closes around early-October, when overnight lows resume dipping below freezing and frost-tender plants need protection or harvest. These dates represent 30-year central tendencies; actual year-to-year variation can shift either bookend by 7-14 days, and local microclimate features within Pecatonica — cold-air drainage on calm clear nights, slope aspect, distance from any nearby lake or river — can push the practical frost window earlier or later than the regional average.
Similar climates: Westlake Village, IL, Ridott, IL, Winnebago, IL, Davis, IL, Durand, IL.
Frequently asked
- When does it freeze in Pecatonica?
- Pecatonica's last spring frost typically falls around mid-May, and the first fall frost arrives around mid-October.
- What is the rainy season in Pecatonica?
- June is the wettest month with about 5.3 inches of rain on average; the city receives roughly 38 inches annually.
- What is the warmest month in Pecatonica?
- July is typically warmest, averaging about 72°F.
- What is the coldest month in Pecatonica?
- January is typically coldest, averaging about 20°F.
- When can I start a vegetable garden in Pecatonica?
- 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 Pecatonica get?
- Pecatonica averages about 69 rainy days per year.
- What hardiness zone is Pecatonica?
- Pecatonica'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
Pecatonica, Illinois sits in a warm-summer humid continental climate zone. January means hover near 20°F while July averages 72°F — a 53°F seasonal swing.
Across the year, Pecatonica receives about 38 inches of precipitation spread over roughly 69 rainy days.
The rhythm of the year is set by latitude (42.3°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.