The average temperature in Killleen, TX the average temperature is 37.93 degrees in summer, with precipitation around 12.0 mm , Denver's temperatures reach 34.63 during the hot season, with 12.0 average of rain rate . In winter, however, weather indicators show around -17.82 degrees in Denver, compared to the -4.16 average degrees reported in Killleen, TX. During the winter period, Killleen, TX can register 3.0 mm precipitation, while Denver have an average of 9.0 mm rain level.