Round Rock, Texas Weather
Thunder quiets the land. Day 93 of summer. Read this microseason across nine climate regions →
Round Rock weather forecast — hour by hour, 7-day outlook, NOAA radar
Conditions updated 9:20 AM CDT · Open-Meteo
- TodaySep 21Clear24%—96°73°—
- TuesdaySep 22Clear16%0.02″94°73°-2°
- WednesdaySep 23Light Drizzle11%—96°73°+2°
- ThursdaySep 24Overcast——98°77°+2°
- FridaySep 25Overcast——98°76°0°
- SaturdaySep 26Overcast——97°76°-1°
- SundaySep 27Overcast——98°76°+1°
Air quality now AQI 49 · Good
AQI 49 (Good), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 9.8 µg/m³ (AQI 52) with a 0.75 fine-to-coarse ratio and 1 mph wind — combustion smoke trapped in stagnant air, not road dust.
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 30 now. With UV 2.6 peaking around 1 PM under partly cloudy skies, surface ozone likely climbs to AQI 7.
- Present
- AQI 30
- UV peak
- 2.6 at 1 PM
- Sky at peak
- partly cloudy
- Projected peak
- AQI 7
PM × Wind × Precip
PM2.5 at 9.8 µg/m³ (AQI 52) with a 0.75 fine-to-coarse ratio and 1 mph wind — combustion smoke trapped in stagnant air, not road dust.
- PM2.5/PM10
- 0.75
- Wind
- calm
- 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).
September dries up ditches or breaks down bridges.
- Moonrise
- 4:40 PM
- Moonset
- 2:20 AM
- In sign
- ♑︎ Capricorn
Thunder quiets the land
Read this microseason across nine climate regions →
All 72 microseasons on the year wheel →
Round Rock at a glance
- Today vs. normal: Today averages 85°F (high 96°F, low 73°F), 9°F above the 76°F normal for Sep 21
- Last frost: March 11 (1991–2020 median, NOAA station 16 km away)
- Microseason: Sep 21–25
- Planting calendar: September — plant beans, squash, fall brassicas, carrots; harvest beans, summer squash, winter squash
16-Day Forecast — Round Rock
- Mon96°73°24%
- Tue94°73°16%
- Wed96°73°11%
- Thu98°77°5%
- Fri98°76°1%
- Sat97°76°3%
- Sun98°76°6%
- Mon97°76°15%
- Tue82°73°31%
- Wed89°70°22%
- Thu91°72°14%
- Fri83°70°13%
- Sat85°70°16%
- Sun87°69°11%
- Mon79°60°7%
- Tue78°55°16%
Forecast data from Open-Meteo (CC BY 4.0).
Live wind & temperature near Round Rock
Interactive wind and temperature map centered on Round Rock — it loads in your browser. Open the full weather map.
Right now in the garden
Late season
As of September 21, the first frost (around November 20) is about 9 weeks away. Frost-tender plants keep producing until then. This city's planting calendar for September: plant beans, squash, fall brassicas, and carrots; harvest beans, summer squash, and winter squash.
SPC Convective Outlook
Storm Prediction Center — Round Rock
SPC includes Round Rock in the general thunderstorm area today — no severe risk, but storms are possible.
- TODAYTSTMGeneral Thunderstorms
- TOMORROWTSTMGeneral Thunderstorms
- 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.
Sun & seasons in Round Rock
Round Rock sits in Williamson County, where the year’s longest day runs 14h 7m of daylight and its shortest just 10h 10m — a swing of +3h 57m between the June and December solstices. Clocks spring forward on Sunday, March 8, 2026 and fall back on Sunday, November 1, 2026.
Houston, the state’s largest city, lies about 145 miles to the ESE. The nearest town Round Rock tracks is Austin, roughly 17 miles to the SSW.
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| February | lettuce, peas, spinach, radishes | — |
| March | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | spinach, radishes |
| April | tomatoes, peppers, beans, squash | lettuce, peas, spinach, radishes |
| May | squash | lettuce, peas, spinach, beans, summer squash, garlic |
| June | squash | tomatoes, peppers, beans, summer squash, garlic |
| July | tomatoes, peppers, beans, squash | tomatoes, peppers, summer squash, winter squash |
| August | tomatoes, peppers, beans, squash | summer squash, winter squash |
| September | beans, squash, fall brassicas, carrots | beans, summer squash, winter squash |
| October | garlic (overwinter) | tomatoes, peppers, beans, summer squash, winter squash |
| November | — | tomatoes, peppers, beans, summer squash, winter squash, fall brassicas, carrots |
| December | — | fall brassicas, carrots |
A year in weather
The year in Round Rock tops out in August (~84°F) and dips lowest in January (~49°F), with October wettest at 4.6 inches and February driest at 2.0 inches.
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 49° | 2.6″ | 7 |
| February | 53° | 2.0″ | 8 |
| March | 60° | 3.0″ | 8 |
| April | 67° | 2.3″ | 7 |
| May | 74° | 4.1″ | 9 |
| June | 81° | 4.4″ | 7 |
| July | 84° | 2.8″ | 6 |
| August | 84° | 2.3″ | 4 |
| September | 78° | 3.4″ | 7 |
| October | 69° | 4.6″ | 6 |
| November | 58° | 2.8″ | 6 |
| December | 50° | 2.8″ | 8 |
Regional context
Similar climates Brushy Creek, TX, Wells Branch, TX, Pflugerville, TX
Round Rock's climate, from NOAA NCEI 1991-2020 station normals, pairs 49°F Januarys with 84°F Julys — a 36°F swing. About 37.1 inches of precipitation falls over roughly 82 days a year.
Rainfall in Round Rock splits evenly between the seasons: October tops out at 4.6 inches over 6.3 rainy days, and February logs 2.0 inches across 7.6 — neither half of Round Rock's year dominates. That lines Round Rock up with places like Brushy Creek, TX, Wells Branch, TX and Pflugerville, TX, fed by overlapping storm tracks.
The cool-season window in Round Rock starts at March 11, when nights stop freezing — think lettuce, chard, arugula, and mustard greens. In Round Rock, warm-season transplants — tomatoes, peppers, basil — wait two weeks past Round Rock's frost date. Round Rock's window closes around November 20 as Round Rock's overnight lows return below freezing. Sheltered Round Rock yards can escape a light frost.
Similar climates: Brushy Creek, TX, Wells Branch, TX, Pflugerville, TX, Hutto, TX, Cedar Park, TX.
Frequently asked
- When does it freeze in Round Rock?
- In Round Rock, expect the last spring frost near March 11; Round Rock's first autumn frost comes around November 20.
- What is the rainy season in Round Rock?
- Rainfall in Round Rock peaks in October near 4.6 inches, out of about 37 inches annually.
- What is the warmest month in Round Rock?
- On average August tops the year in Round Rock at about 84°F.
- What is the coldest month in Round Rock?
- The coldest stretch in Round Rock falls in January, around 49°F on average.
- When can I start a vegetable garden in Round Rock?
- Hardy spring crops go in near March 11 in Round Rock; tender peppers and squash wait 10–14 days.
- How many rainy days does Round Rock get?
- Expect roughly 82 wet days a year in Round Rock.
- What hardiness zone is Round Rock?
- Because Round Rock bottoms near 49°F in January, that winter low sets Round Rock's USDA zone — verify by ZIP.
- What is the 10-day forecast for Round Rock?
- Round Rock'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 Rock?
- See this week's day-by-day rain chances for Round Rock in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in Round Rock?
- Current conditions for Round Rock 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 Rock forecast updated?
- The Round Rock 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 Rock?
- Today's sunrise and sunset times for Round Rock 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 Rock?
- The next few days in Round Rock's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
Round Rock sits at 30.5°N; its climate zone is humid subtropical (Köppen approximation).
ZIP codes in Round Rock
- 78664
- 78665
- 78681
- 78682
- 78683