Round Rock, Texas climate: NOAA's gridded normals for the city, beside the nearest station records
NOAA's gridded 1991-2020 normals put Round Rock's center at January lows of 38°F and July highs of 96°F, a yearly mean of 67.8°F and 36.3 inches of precipitation. No NOAA station keeps a record under the city's name. The nearest station record, Georgetown (11 miles N, 874 ft), has January lows of 36°F and July highs of 96°F.
135,359 people (Census Bureau 2024). Distances and directions are from the city's center.
- Jan 61° 38°
- Feb 65° 42°
- Mar 72° 49°
- Apr 79° 55°
- May 86° 64°
- Jun 92° 70°
- Jul 96° 73°
- Aug 97° 73°
- Sep 90° 67°
- Oct 81° 57°
- Nov 70° 47°
- Dec 63° 40°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
The months above are NOAA's gridded normals at Round Rock's center.
What is each month like in Round Rock?
NOAA's grid estimates the normals every 5 km or so from the stations around each point, terrain included. It smooths between stations, so night lows at the heart of a large city can run warmer than the grid shows: at five big-city airports we compared, the grid's highs were within about 1°F of the station and its lows 1-6°F cooler. The nearest record's high and low are beside each month.
| Month | High | Low | Mean | Precip. | Georgetown high | Georgetown low |
|---|---|---|---|---|---|---|
| January | 61°F | 38°F | 49.6°F | 2.53 | 60°F | 36°F |
| February | 65°F | 42°F | 53.8°F | 2.17 | 65°F | 40°F |
| March | 72°F | 49°F | 60.5°F | 2.84 | 72°F | 47°F |
| April | 79°F | 55°F | 67.2°F | 2.81 | 79°F | 54°F |
| May | 86°F | 64°F | 75.0°F | 4.53 | 85°F | 63°F |
| June | 92°F | 70°F | 81.3°F | 3.52 | 92°F | 70°F |
| July | 96°F | 73°F | 84.3°F | 2.28 | 96°F | 72°F |
| August | 97°F | 73°F | 84.6°F | 2.49 | 97°F | 72°F |
| September | 90°F | 67°F | 78.5°F | 3.46 | 90°F | 67°F |
| October | 81°F | 57°F | 69.1°F | 4.05 | 81°F | 57°F |
| November | 70°F | 47°F | 58.7°F | 2.86 | 70°F | 46°F |
| December | 63°F | 40°F | 51.1°F | 2.74 | 62°F | 38°F |
In metric: a yearly mean of 19.9°C, January lows of 3°C, July highs of 35°C and 922 mm of precipitation a year.
Source: NOAA NCEI U.S. Monthly Gridded Climate Normals 1991-2020 (nClimGrid, accession 0245564); NOAA NCEI 1991-2020 station normals. The grid cell holding the city's Census center point.
What do the station records around Round Rock say?
Each row is a NOAA station's own 1991-2020 normals, with the snow and frost dates the grid does not give. A record downhill or nearer the coast than the city can run warmer, one uphill cooler: compare the elevations.
| Record | Where | Elevation | Year | Jan low | Jul high | Precip. | Snow | Last frost |
|---|---|---|---|---|---|---|---|---|
| GeorgetownGeorgetown Lake | 11 mi N | 874 ft | 67.1°F | 36°F | 96°F | 37.1 | 0 | March 6 |
| Taylor1 mi NW | 15 mi E | 571 ft | 67.4°F | 37°F | 95°F | 37.1 | 0 | March 8 |
| AustinAustin-Camp Mabry | 15 mi S | 670 ft | 70.0°F | 42°F | 97°F | 36.3 | 0 | February 20 |
Source: NOAA NCEI 1991-2020 U.S. Climate Normals; place center and population: Census Bureau 2024. Last frost: the median last spring date of 32°F.
How much snow, how late a frost, what zone and how much sun in Round Rock?
NOAA's grid gives no snow, frost dates or records, so these come from the nearest station record, Georgetown (11 miles N, 874 ft). It gets 0 inches of snow in a normal year. The last spring frost (32°F) comes after March 6 in half of years and the first autumn frost before November 24.
The USDA's 2023 Plant Hardiness Zone Map puts Round Rock in zone 9a across its 3 ZIP code areas.
Over a year 79% of the sunlight that would reach the ground under clear skies gets through the clouds in the area (4.8 kWh per square metre a day, NASA POWER 2001-2020); August is the sunniest month (88%) and February the cloudiest (68%).
Georgetown's page has its months, frost probabilities, records by month and recent years. NOAA's grid has monthly figures only, so there are no day-by-day month pages for Round Rock; the nearest record's month pages have them.
Source: NOAA NCEI 1991-2020 normals, station USC00413507; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; sunshine: NASA POWER.
How does the climate vary across Round Rock, ZIP code by ZIP code?
3 ZIP code areas lie wholly or partly in Round Rock. On NOAA's grid 78664 is the warmest (67.8°F a year) and 78665 the coolest (67.7°F), so the city is nearly uniform. Each row also names the nearest station record and its frost dates.
| ZIP code | Zone | Year | Jan low | Jul high | Precip. | Nearest record | Last frost | First frost |
|---|---|---|---|---|---|---|---|---|
| 78664 | 9a | 67.8°F | 38°F | 96°F | 36.3 | Georgetown (13 mi) | March 6 | November 24 |
| 78665 | 9a | 67.7°F | 38°F | 96°F | 36.2 | Georgetown (10 mi) | March 6 | November 24 |
| 78681 | 9a | 67.8°F | 38°F | 96°F | 36.1 | Georgetown (9 mi) | March 6 | November 24 |
Source: Census Bureau 2020 ZCTA-to-place relationship file and ZCTA centers; NOAA NCEI gridded and station normals, 1991-2020. A ZIP area counts when at least a tenth of its land (and 0.5 km²) is in the city; its figures are the grid cell at its center; frost dates are the nearest record's medians of 32°F.