Round Lake Beach, Illinois Weather
Day 93 of summer. Read today’s microseason across nine climate regions →
Round Lake Beach weather forecast — hour by hour, 7-day outlook, NOAA radar
Conditions updated 9:21 AM CDT · Open-Meteo
- TodaySep 21Overcast11%—63°57°—
- TuesdaySep 22Overcast——60°53°-3°
- WednesdaySep 23Light Drizzle—0.01″64°54°+4°
- ThursdaySep 24Overcast——66°55°+2°
- FridaySep 25Overcast——60°58°-6°
- SaturdaySep 26Light Rain—0.35″59°53°-1°
- SundaySep 27Drizzle14%0.06″69°54°+10°
Air quality now AQI 30 · Good
AQI 30 (Good), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 5.9 µg/m³, PM10 at 6.0 µg/m³ — typical background levels with no transport signature.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion during the projected peak around 6 PM.
What's driving it
PM × Wind × Precip
PM2.5 at 5.9 µg/m³, PM10 at 6.0 µg/m³ — typical background levels with no transport signature.
- PM2.5/PM10
- 0.98
- Wind
- breezy
- 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).
September dries up ditches or breaks down bridges.
- Moonrise
- 4:32 PM
- Moonset
- 1:05 AM
- In sign
- ♑︎ Capricorn
Round Lake Beach at a glance
- Today vs. normal: Today averages 60°F (high 63°F, low 57°F), 4°F below the 64°F normal for Sep 21
- Last frost: April 24 (1991–2020 median, NOAA station 6 km away)
- Microseason: Sep 21–25
- Planting calendar: September — plant garlic (overwinter); harvest tomatoes, peppers, beans, summer squash, winter squash
16-Day Forecast — Round Lake Beach
- Mon63°57°11%
- Tue60°53°7%
- Wed64°54°5%
- Thu66°55°0%
- Fri60°58°0%
- Sat59°53°5%
- Sun69°54°14%
- Mon75°56°12%
- Tue70°57°24%
- Wed70°50°26%
- Thu62°50°11%
- Fri58°50°17%
- Sat73°58°23%
- Sun59°47°19%
- Mon53°39°16%
- Tue57°36°19%
Forecast data from Open-Meteo (CC BY 4.0).
Live wind & temperature near Round Lake Beach
Interactive wind and temperature map centered on Round Lake Beach — it loads in your browser. Open the full weather map.
Right now in the garden
Fall planting + final harvests
As of September 21, the season's first frost (typically October 23) is approaching. Pick what frost-tender plants still carry before the next cold front. This city's planting calendar for September: plant garlic (overwinter); harvest tomatoes, peppers, beans, summer squash, and winter squash.
Sun & seasons in Round Lake Beach
Round Lake Beach sits in Lake County, where the year’s longest day runs 15h 17m of daylight and its shortest just 9h 4m — a swing of +6h 13m between the June and December solstices. Clocks spring forward on Sunday, March 8, 2026 and fall back on Sunday, November 1, 2026.
Chicago, the state’s largest city, lies about 43 miles to the SSE. The nearest town Round Lake Beach tracks is Palatine, roughly 18 miles to the S.
Air quality in Round Lake Beach
Air quality in Round Lake Beach’s county has held roughly steady since 2020; its cleanest year on record was 2020 (median AQI 39). See the full air-quality history for Round Lake Beach.
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| April | lettuce, peas, spinach, radishes | radishes |
| May | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | lettuce, spinach, radishes |
| June | tomatoes, peppers, beans, squash | lettuce, peas, spinach, radishes |
| July | tomatoes, peppers, beans, squash | lettuce, peas, spinach, beans, summer squash, garlic |
| August | beans, squash, fall brassicas, carrots | tomatoes, peppers, beans, summer squash |
| September | garlic (overwinter) | tomatoes, peppers, beans, summer squash, winter squash |
| October | garlic (overwinter) | tomatoes, peppers, beans, summer squash, winter squash, fall brassicas, carrots |
| November | — | fall brassicas, carrots |
A year in weather
Round Lake Beach peaks at about 75°F in July and bottoms near 22°F in January; May brings the heaviest rain (3.7 inches) and January the least (1.8 inches).
| Month | Mean temp | Precip |
|---|---|---|
| January | 22° | 1.8″ |
| February | 24° | 1.9″ |
| March | 35° | 2.7″ |
| April | 47° | 3.4″ |
| May | 57° | 3.7″ |
| June | 68° | 3.4″ |
| July | 75° | 2.5″ |
| August | 74° | 2.8″ |
| September | 67° | 3.1″ |
| October | 54° | 2.9″ |
| November | 39° | 3.2″ |
| December | 26° | 2.3″ |
Regional context
Similar climates Round Lake Heights, IL, Venetian Village, IL, Long Lake, IL
Round Lake Beach swings from 22°F in January to 75°F in July (53°F) per modelled 1991-2020 normals (EC_Earth3P_HR model via Open-Meteo); precipitation in Round Lake Beach runs about 33.6 inches.
Round Lake Beach's precipitation spreads evenly across the seasons: May peaks at 3.7 inches, while January holds 1.8 inches — no season dominates Round Lake Beach's rain calendar. That lines Round Lake Beach up with places like Round Lake Heights, IL, Venetian Village, IL and Long Lake, IL, fed by overlapping storm tracks.
Once Round Lake Beach passes April 24, freezes fade and Round Lake Beach's beds take kale, peas, spinach, and parsnips. Heat-demanding starts go out a fortnight on in Round Lake Beach, after the soil warms and cold snaps clear. The season ends by October 23 in Round Lake Beach, once hard frosts set back in. That date is a median: Round Lake Beach freezes sooner in half of years.
Similar climates: Round Lake Heights, IL, Venetian Village, IL, Long Lake, IL, Hainesville, IL, Lake Villa, IL.
Frequently asked
- When does it freeze in Round Lake Beach?
- Round Lake Beach's last spring frost lands near April 24, and in Round Lake Beach the first fall frost follows around October 23.
- What is the rainy season in Round Lake Beach?
- Rainfall in Round Lake Beach peaks in May near 3.7 inches, out of about 34 inches annually.
- What is the warmest month in Round Lake Beach?
- Round Lake Beach peaks in July, when the mean runs near 75°F.
- What is the coldest month in Round Lake Beach?
- January is Round Lake Beach's coldest month, averaging about 22°F.
- When can I start a vegetable garden in Round Lake Beach?
- In Round Lake Beach, sow peas and hardy greens around April 24; Round Lake Beach's tomatoes and peppers wait two weeks more.
- What hardiness zone is Round Lake Beach?
- With January around 22°F, Round Lake Beach's zone reflects that minimum — the USDA ZIP map confirms Round Lake Beach's band.
- What is the 10-day forecast for Round Lake Beach?
- Round Lake Beach's extended outlook — daily high and low temperatures and precipitation chances for each upcoming day — is in the daily forecast above.
- Will it rain this week in Round Lake Beach?
- See this week's day-by-day rain chances for Round Lake Beach in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in Round Lake Beach?
- Current conditions for Round Lake Beach and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the Round Lake Beach forecast updated?
- The Round Lake Beach forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in Round Lake Beach?
- Today's sunrise and sunset times for Round Lake Beach are in the Almanac section above, along with civil dawn, civil dusk, and day length. Day length is longest near the summer solstice and shortest near the winter solstice.
- How accurate is the weather forecast for Round Lake Beach?
- The next few days in Round Lake Beach's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
Round Lake Beach sits at 42.4°N; its climate zone is warm-summer humid continental (Köppen approximation).
ZIP codes in Round Lake Beach
- 60073