Weather on December 21
Round Rock, TX
55 Years of Data
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° | — | — |
Round Rock, TX Temperature Range by Month
Average monthly highs and lows. The shaded band shows the typical daily temperature range.
Round Rock, TX Monthly Precipitation
Average rainfall and snowfall per month, in inches.
Round Rock, TX Daily Temperature Calendar
Average daily high temperature for every day of the year. Each cell is the climatological mean for that calendar day across 55 years of NOAA data.
Best Time to Visit Round Rock, TX
Round Rock, TX has no months that meet our "pleasant" threshold — every season has tradeoffs.