Weather & Climate
Climate anomaly calculator.
Put an observed temperature and precipitation amount beside a climate normal to quantify warmer, cooler, wetter, or drier conditions.
Normal and observed values
Climate context
Fill the form and press Calculate.
What is a climate normal?
NOAA describes a climate normal as a 30-year average of a variable for a uniform period. The anomaly is simply the observation minus that normal. Precipitation is also shown as a percent of normal, which is useful when the same amount has a different meaning across dry and wet climates.
Sources: NOAA NCEI U.S. Climate Normals and the NCEI/WMO global normals overview. Enter a normal and observation from the same location, period, unit, and measurement definition.
Context, not attribution
A single anomaly describes one comparison; it does not by itself establish a climate trend or explain why conditions were unusual.