Over 40 climate indices

Climate Indices are indicators calculated from weather variables. The indices we provide were defined by the joint CCl/CLIVAR/JCOMM Expert Team (ET) on Climate Change Detection and Indices (ETCCDI) and can be found here. They are widely used by scientist and adaptation practitioners to evaluate climate variability and change.

From precipitation (18 indices)

Precipitation days Index: Number of days with precipitation exceeding 5 mm/day
Heavy precipitation days Index: number of days with precipitation exceeding 10 mm/day
Very heavy precipitation days Index: number of days with precipitation exceeding 20 mm/day
Dry days Index: number of consecutive days with no precipitation (< 1 mm)
Consecutive Dry days Index: largest number of consecutive Dry days
Number of consecutive Dry days periods: number of 5-consecutive Dry days periods
Wet Days Index: number of days with precipitation (> 1 mm)
Consecutive wet days Index: largest number of consecutive Wet days
Number of consecutive wet days periods: number of 5-consecutive Wet days period
Moderate wet days: Percentage of Moderate Wet Days (precipitation> 75th percentile) during Wet days
Wet days: Percentage of Wet Days (precipitation > 90th percentile ) during Wet days
Very wet days: Percentage of Very Wet Days (precipitation > 95th percentile ) during Wet days
Precipitation fraction due to moderate wet days
Precipitation fraction due to wet days
Precipitation fraction due to very wet days
Highest one day precipitation amount
Highest 5 days precipitation amount
Mean precipitation amount at wet days


From mean temperature (7 indices)

Cold days Index: Percentage of days, centered on a five-day window, with temperature below the 10th percentile
Warm days Index: Percentage of days, centered on a five-day window, with temperature above the 90th percentile
Cold-spell days Index: Days in intervals of at least 6 days with temperature < 10th percentile) 
Cold-spell days periods: periods in intervals of at least 6 days with temperature < 10th percentile
Warm-spell days Index: days in intervals of at least 6 days with temperature < 10th percentile
Warm spell days periods: periods in intervals of at least 6 days with temperature > 90th percentile
Heating degree days : sum of degrees below 18°C.

From maximum temperature (8 indices)

Very cold days: Percentage of days, centered on a five-day window, with temperature below the 10th percentile
Very warm days: Percentage of days, centered on a five-day window, with temperature above the 90th percentile
Ice days Index: number of days with temperature below 0°C
Summer days Index: number of days with temperature above 25°C
Consecutive summer days Index: largest number of consecutive Summer days
Consecutive summer days periods: _number of 5-consecutive Summer days periods
Heat wave duration Index: largest number of consecutive days with temperature + 5°C the average
Heat wave duration periods: number of 6 consecutive days periods with temperature + 5°C the average

From minimum temperature (8 indices)

Cold nights days: Percentage of days, centered on a five-day window, with temperature below the 10th percentile
Warm nights days: Percentage of days, centered on a five-day window, with temperature above the 90th percentile
Tropical nights days Index: number of days with temperature above 20°C
Frost days Index (< 0°C): number of days with temperature below 0°C
Consecutive frost days Index: largest number of consecutive Frost days
Consecutive frost days periods: number of periods of five consecutive days with temperature below 0°C
Cold wave duration Index: largest number of consecutive days with temperature - 5°C the average
Cold wave duration periods: number of 6 consecutive days periods with temperature - 5°C the average

Updated on: 07/02/2023