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Determining the average temperature of a region or period provides a clearer climate picture than a single reading ever could. Daily highs and lows, seasonal shifts, and geographic differences mean temperatures fluctuate constantly. By calculating the mean—adding all measured values and dividing by the number of readings—you obtain a reliable temperature estimate for your analysis.
Before gathering data, decide what you need the average for. Are you measuring a single week in one location, a day across multiple sites, or a longer span? The calculation method stays the same, but the data you collect will differ.
Gather your own readings or pull existing data from reputable sources. The National Centers for Environmental Information (NCEI), part of NOAA, offers comprehensive U.S. temperature datasets. If you need a weekly average, record a temperature at the same time each day in the same spot. For broader analyses, existing datasets often provide the necessary breadth.
Temperature can be expressed in Celsius, Kelvin, or Fahrenheit, but consistency is key for accurate averaging. Convert all values to a single unit:
With all readings in the same unit, add them together. For example, a week's Fahrenheit readings might be 70, 68, 79, 78, 73, 69, and 72:
sum = 70 + 68 + 79 + 78 + 73 + 69 + 72 = 509.
Compute the mean by dividing the total by the count of measurements:
average temperature = 509 ÷ 7 = 72.7 °F.
You can extend this method by first averaging daily temperatures, then averaging those daily means to obtain a weekly average.
