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Definitions of climate indices

Definitions of temperature indices set A

Index Abbreviation Definition Temporal resolution Unit
Summer days sd Number of days with maximum temperature > 25°C Annual (Jan-Dec) Days
Hot days hd Number of days with maximum temperature > 30°C Annual (Jan-Dec) Days
Tropical nights #1 tn1 Number of days with minimum temperature > 20°C Annual (Jan-Dec) Days
Tropical nights #2 tn2 Number of days with minimum temperature > 22°C Annual (Jan-Dec) Days
Frost days fd Number of days with minimum temperature ≤ 0°C Annual (Jul-Jun) Days
Consecutive frost days cfd Maximum number of consecutive days with minimum temperature ≤ 0°C Annual (Jul-Jun) Days
Ice days id Number of days with maximum temperature ≤ 0°C Annual (Jul-Jun) Days
Freeze-thaw days ft1 Number of days with minimum temperature ≤ 0°C and maximum temperature > 0°C Annual (Jul-Jun) Days
Freeze-thaw days - spring ft2 Number of days with minimum temperature ≤ 0°C & maximum temperature > 0°C Jan-Apr Days
Growing degree-days gdd5 Sum of degrees with mean temperature > 5°C Annual (Jan-Dec) °C
Cooling degree-days cdd Sum of degrees with mean temperature < 18°C Annual (Jan-Dec) °C
Heating degree-days hdd Sum of degrees with mean temperature > 18°C Annual (Jan-Dec) °C
Frost-free season FFS Maximum number of consecutive days with minimum temperature > 0°C Annual (Jan-Dec) Days
Frost-free season starting date FFSs Starting date of frost-free season n/a Date
Frost-free season ending date FFSe Ending date of frost-free season n/a Date
Growing season GS start when mean temperature > 5°C for 6 days and end when mean temperature < 5°C for 6 days Annual (Mar-Nov) Days
Growing season starting date GSs Starting date of growing season n/a Date
Growing season ending date GSe Ending date of growing season n/a Date

Definitions of temperature indices set B

Abbreviation Definition Time Period Unit
WinTx05 Winter 5th percentile of maximum temperature Dec-Jan-Feb °C
WinTx95 Winter 95th percentile of maximum temperature Dec-Jan-Feb °C
WinTn05 Winter 5th percentile of minimum temperaure Dec-Jan-Feb °C
WinTn95 Winter 95th percentile of minimum temperature Dec-Jan-Feb °C
SprTx05 Spring 5th percentile of maximum temperature Mar-Apr-May °C
SprTx95 Spring 95th percentile of maximum temperature Mar-Apr-May °C
SprTn05 Spring 5th percentile of minimum temperature Mar-Apr-May °C
SprTn95 Spring 95th percentile of minimum temperature Mar-Apr-May °C
SumTx05 Summer 5th percentile of maximum temperature Jun-Jul-Aug °C
SumTx95 Summer 95th percentile of maximum temperature Jun-Jul-Aug °C
SumTn05 Summer 5th percentile of minimum temperature Jun-Jul-Aug °C
SumTn95 Summer 95th percentile of minimum temperature Jun-Jul-Aug °C
AutTx05 Autumn 5th percentile of maximum temperature Sep-Oct-Nov °C
AutTx95 Autumn 95th percentile of maximum temperature Sep-Oct-Nov °C
AutTn05 Autumn 5th percentile of minimum temperature Sep-Oct-Nov °C
AutTn95 Autumn 95th percentile of minimum temperature Sep-Oct-Nov °C

Definitions of precipitation indices

Index Abbreviation Definition Resolution Unit
Days with rainfall nd_r Number of days with rain ≥ 1 mm Annual (Jan-Dec) Days
Days with snowfall nd_s Number of days with snow ≥ 1 mm Annual (Jul-Jun) Days
Days with precipitation nd_p Number of days with precipitation ≥ 1 mm Annual (Jan-Dec) Days
Days with heavy rainfall h1_r Number of days with rain > 90th percentile Annual (Jan-Dec) days
Days with heavy snowfall h1_s Number of days with snow > 90th percentile Annual (Jul-Jun) Days
Days with heavy precipitation h1_p Number of days with precipitation > 90th percentile Annual (Jan-Dec) Days
Highest 1-day rainfall x1_r Highest 1-day rain Annual (Jan-Dec) mm
Highest 1-day rainfall x1_s Highest 1-day snow Annual (Jul-Jun) mm
Highest 1-day precipitation x1_p Highest 1-day precipitation Annual (Jan-Dec) mm
Maximum number of consecutive dry days mcdd Max number of days with precipitation < 1 mm Annual (Jan-Dec) Days
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