Monthly HLA (high-low average) for Killeen, Texas, based on my own records, from 2010 through July 2018. Monthly HLAs are calculated by average all the daily HLAs for the month.
I came up with “HLA” as a way to compare days or months from different years. Sometimes the high would be the same, but the low would be different, or vice versa. The monthly HLAs in this graph are averaged from the daily HLAs.
These temperatures aren't official. The official temperatures for Killeen come from the airport, outside the city to the southwest, where almost no one lives, works, or shops. These temperatures are from my house.
Update: In April 2017, I added the two "trend lines". The reddish one shows that our hottest months have gotten slightly cooler over the years, while our coldest months are warming.