Arnold, Maryland Weather
Cicadas claim the afternoon. Day 14 of summer. Read this microseason across nine climate regions →
Arnold weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJul 4Showers40%0.49″101°78°—
- SundayJul 5Light Rain46%0.07″95°76°-6°
- MondayJul 6Drizzle72%0.03″82°74°-13°
- TuesdayJul 7Thunderstorm72%0.07″87°72°+5°
- WednesdayJul 8Heavy Showers37%0.50″78°70°-9°
- ThursdayJul 9Partly Cloudy12%—93°69°+15°
- FridayJul 10Light Drizzle39%0.01″95°73°+2°
AQI 182 (Unhealthy), driven by Ozone. AQI up 117 in the last 6 hours — air quality is degrading. Ozone at AQI 117. Overcast through the UV peak window (cloud cover ~82%) — afternoon ozone should stay flat.
LIMIT OUTDOORS Limit prolonged outdoor exertion. Sensitive groups should avoid outdoor exertion. Consider rescheduling outdoor activities until AQI improves.
What's driving it
Ozone × UV × Sky
Ozone at AQI 117. Overcast through the UV peak window (cloud cover ~82%) — afternoon ozone should stay flat.
- Present
- AQI 117
- UV peak
- 0.2 at 1 PM
- Sky at peak
- overcast
- Projected peak
- AQI 14
PM × Wind × Precip
PM scrubbed by 3 hours of recent rain — PM2.5 down to 9.1 µg/m³, PM10 to 9.5 µg/m³.
- PM2.5/PM10
- 0.96
- Wind
- light
- Recent rain
- 3h in last 6h
- Pattern
- washed out
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).
If the first of July be rainy weather, 'twill rain more or less for four weeks together.
- Moonrise
- 10:58 PM
- Moonset
- 10:10 AM
- In sign
- ♓︎ Pisces
Cicadas claim the afternoon
Arnold at a glance
- Today vs. normal: 13°F above the seasonal normal for this latitude
- Last frost: April 10 (climatological average for this latitude)
- Microseason: Jul 1–5
- Planting window: Harvest early potatoes. Begin drying onions on the surface.
ZIP code: 21012
16-Day Forecast — Arnold
- Sat101°78°40%
- Sun95°76°46%
- Mon82°74°72%
- Tue87°72°72%
- Wed78°70°37%
- Thu93°69°12%
- Fri95°73°39%
- Sat92°71°33%
- Sun83°71°20%
- Mon79°71°19%
- Tue88°69°19%
- Wed89°72°40%
- Thu94°71°42%
- Fri93°73°35%
- Sat93°71°35%
- Sun93°72°39%
Forecast data from Open-Meteo (CC BY 4.0).
Right now in the garden
Peak growing season
As of July 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 — Arnold
SPC has placed Arnold in the Enhanced Risk category for severe thunderstorms today.
- TODAYENHEnhanced Risk
- TOMORROWSLGTSlight Risk
- DAY 3TSTMGeneral Thunderstorms
Numerous severe storms likely. Tornadoes, large hail, and damaging wind gusts possible across the area. Track NWS warnings if storms develop.
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.
ZIP codes in Arnold
- 21012