Marengo, Illinois Weather
Fireflies rise from the lawn. Day 77 of spring. Read this microseason across nine climate regions →
Marengo weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 3Overcast——81°49°—
- ThursdayJun 4Overcast——84°58°+3°
- FridayJun 5Rain78%0.30″76°66°-8°
- SaturdayJun 6Heavy Showers64%0.76″85°63°+9°
- SundayJun 7Overcast11%—80°64°-5°
- MondayJun 8Light Showers23%0.01″75°64°-5°
- TuesdayJun 9Drizzle22%—82°69°+7°
PM2.5 at 8.7 µg/m³ (AQI 48) with a 0.83 fine-to-coarse ratio and 5 mph wind — combustion smoke trapped in calm air, not road dust. AQI up 30 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 40. Overcast through the UV peak window (cloud cover ~100%) — afternoon ozone should stay flat.
- Present
- AQI 40
- UV peak
- 0.0 at 1 PM
- Sky at peak
- overcast
- Projected peak
- AQI 5
PM × Wind × Precip
PM2.5 at 8.7 µg/m³ (AQI 48) with a 0.83 fine-to-coarse ratio and 5 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.83
- 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
- 4:31 AM
- Moonset
- 1:49 PM
- In sign
- ♑︎ Capricorn
Fireflies rise from the lawn
Marengo at a glance
- Today vs. normal: 4°F below the seasonal normal for this latitude
- Last frost: April 29 (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 — Marengo
SPC has placed Marengo 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.