Weather on December 21
Round Rock, TX
55 Years of Data
Avg High
64°F
Avg Low
39°F
Warmest
2010
66°F avg
Coldest
1976
34°F avg
About This Date
December 21st in Round Rock, TX typically brings mild winter weather, with average highs around 64°F and lows near 39°F — a 25°F daily swing. Over 30 years of records, the warmest December 21st was in 2010 (66°F average), while the coldest was 1976 (34°F) — a 32°F range across recorded history. Rain or other precipitation has occurred on about 10% of December 21st dates historically, with the wettest December 21st recording 0.91" of rain.
Planning for December 21st in Round Rock, TX? Great weather for outdoor activities.
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 75° | 46° | 61° | — | — |
| 2024 | 65° | 35° | 50° | — | — |
| 2023 | 70° | 50° | 60° | 0.08" | — |
| 2022 | 48° | 36° | 42° | — | — |
| 2021 | 58° | 35° | 46° | — | — |
| 2020 | 65° | 35° | 50° | — | — |
| 2019 | 49° | 46° | 47° | 0.91" | — |
| 2018 | 63° | 37° | 50° | — | — |
| 2017 | 70° | 44° | 57° | — | — |
| 2016 | 57° | 33° | 45° | — | — |
| 2015 | 65° | 52° | 58° | — | — |
| 2014 | 58° | 46° | 52° | — | — |
| 2013 | 70° | 41° | 55° | 0.46" | — |
| 2012 | 67° | 31° | 49° | — | — |
| 2011 | 58° | 41° | 49° | — | — |
| 2010warmest | 76° | 57° | 66° | — | — |
| 2009 | 62° | 31° | 46° | — | — |
| 2008 | 78° | 35° | 57° | — | — |
| 1982 | 74° | 43° | 58° | — | — |
| 1981 | 76° | 44° | 60° | — | — |
| 1980 | 39° | 31° | 35° | — | — |
| 1979 | 70° | 60° | 65° | — | — |
| 1978 | 70° | 36° | 53° | — | — |
| 1977 | 51° | 36° | 43° | — | — |
| 1976coldest | 45° | 23° | 34° | — | — |
| 1975 | 60° | 30° | 45° | — | — |
| 1974 | 73° | 31° | 52° | — | — |
| 1973 | — | 20° | — | — | — |
| 1972 | 70° | 44° | 57° | — | — |
| 1971 | 76° | 43° | 59° | — | — |
30 years of data from GEORGETOWN