Scale used throughout the year to determine placement and color of temperature at a gathered from NOAA and the daily temperature high and low where I was living at that moment in time.
Temperature data is gathered from the NOAA (National Oceanic and Atmospheric Administration) U.S. Climate Normals from 1981 - 2010. Excerpts from NOAA’s description of their data included below.
…The official normals are calculated for a uniform 30 year period, and consist of annual/seasonal, monthly, daily, and hourly averages and statistics of temperature, precipitation, and other climatological variables from almost 15,000 U.S. weather stations. NCEI generates the official U.S. normals every 10 years in keeping with the needs of our user community and the requirements of the World Meteorological Organization (WMO) and National Weather Service (NWS)...
See https://www.ncei.noaa.gov/products/land-based-station/us-climate-normals for more information about this data.