Normalized difference between daily mean temperature and the 30-year average mean temperature for the past twelve months
The plot shows how much warmer or colder than normal each day in the time period was compared with the temperature on that date in an average year. Dates in blue are colder than normal, and those in red are warmer.
The units are standard deviations from the mean difference. 66% of the variation will be within ±1 standard deviation and 95% is within ±2 standard deviations. A plot with units in degrees is also available.