Sycamore, Illinois Weather
Fireflies rise from the lawn. Day 77 of spring. Read this microseason across nine climate regions →
Sycamore weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 3Overcast——82°49°—
- ThursdayJun 4Overcast——86°57°+4°
- FridayJun 5Showers77%0.04″77°67°-9°
- SaturdayJun 6Heavy Showers68%0.85″83°63°+6°
- SundayJun 7Drizzle15%—80°65°-3°
- MondayJun 8Light Showers24%0.01″78°65°-2°
- TuesdayJun 9Light Drizzle23%—84°69°+6°
PM2.5 at 7.7 µg/m³ (AQI 43) with a 0.82 fine-to-coarse ratio and 5 mph wind — combustion smoke trapped in calm air, not road dust. AQI up 24 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 42. Overcast through the UV peak window (cloud cover ~100%) — afternoon ozone should stay flat.
- Present
- AQI 42
- UV peak
- 0.1 at 1 PM
- Sky at peak
- overcast
- Projected peak
- AQI 5
PM × Wind × Precip
PM2.5 at 7.7 µg/m³ (AQI 43) with a 0.82 fine-to-coarse ratio and 5 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.82
- 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
- 1:50 PM
- In sign
- ♑︎ Capricorn
Fireflies rise from the lawn
Sycamore at a glance
- Today vs. normal: 74°F — typical for the season
- 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 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 — Sycamore
SPC has placed Sycamore 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.