Markham, Illinois Weather
Fireflies rise from the lawn. Day 76 of spring. Read this microseason across nine climate regions →
Markham weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 3Overcast——84°50°—
- ThursdayJun 4Overcast——88°59°+4°
- FridayJun 5Drizzle62%—82°70°-6°
- SaturdayJun 6Showers62%—82°67°0°
- SundayJun 7Overcast19%—78°59°-4°
- MondayJun 8Drizzle20%—85°67°+7°
- TuesdayJun 9Light Drizzle18%—84°70°-1°
Ozone at AQI 73 now. AQI flat over the last 6 hours (within ±3 points). With UV 7.6 peaking around 1 PM under partly cloudy skies, surface ozone likely climbs to AQI 52 by mid-afternoon.
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 73 now. With UV 7.6 peaking around 1 PM under partly cloudy skies, surface ozone likely climbs to AQI 52 by mid-afternoon.
- Present
- AQI 73
- UV peak
- 7.6 at 1 PM
- Sky at peak
- partly cloudy
- Projected peak
- AQI 52
PM × Wind × Precip
PM2.5 at 6.1 µg/m³, PM10 at 7.2 µg/m³ — typical background levels with no transport signature.
- PM2.5/PM10
- 0.85
- 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).
The higher the clouds, the finer the weather.
- Moonrise
- 3:49 AM
- Moonset
- 12:43 PM
- In sign
- ♑︎ Capricorn
Fireflies rise from the lawn
Markham at a glance
- Today vs. normal: 8°F above the seasonal normal for this latitude
- Last frost: April 26 (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 — Markham
SPC has placed Markham in the General Thunderstorms category for severe thunderstorms day after tomorrow.
- TODAYNONENo severe risk
- TOMORROWNONENo severe risk
- DAY 3TSTMGeneral Thunderstorms
Thunderstorms possible. Not severe, but capable of producing lightning and brief heavy rain.
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.