Disclaimer for climate data

Please be advised that certain irregularities have been observed regarding two parameters in the climate data service. The two parameters are 

  • potential evaporation calculated with the Penman equation (pot_evaporation_penman), and
  • the Drought Index (drought_index).

DMI therefore recommends that instead of using the parameter potential evaporation calculated with the Penman equation, please use the parameter potential evaporation calculated with the Makkink equation (pot_evaporation_makkink) instead. 


When the parameter Drought Index is calculated, potential evaporation calculated with the Penman is used as input in the equation for the Drought Index model. This means that there may be a tendency toward a higher Drought Index during the summer.




On this page you can find a table of parameters for which climate data values are available for download through the climate data service. The calculatation methods for the parameter values are described in a separate table.




Table of contents:






Parameters for stationValue

The available parameters are listed below along with a description, the unit of the parameter, and in which resolutions data are available for download. 





stationValue Available for DenmarkstationValue Available for Greenland
NameUnitDescriptionQC performed by DMI's climatologistsHourlyDailyMonthly and yearlyType of day**HourlyDailyMonthly and yearlyType of day**
mean_temp°CMean temperaturexxxxLocal dayxxxOld meteorological day
mean_daily_max_temp°CMean of daily maximum temperaturex -  - xLocal day -  - xOld meteorological day
max_temp_w_date°CMaximum temperature with associated datexxxxLocal dayxxxOld meteorological day
max_temp_12h°CMaximum temperature within the last 12 hoursx -  -  -  - x -  - Old meteorological day
no_ice_daysno. of daysNumber of ice days (maximum temperature < 0°C)x -  - xLocal day -  - xOld meteorological day
no_summer_daysno. of daysNumber of summer days (maximum temperature > 25°C)x -  - xLocal day -  - xOld meteorological day
mean_daily_min_temp°CMean of daily minimum temperaturex -  - xLocal day -  - xOld meteorological day
min_temp°CMinimum temperaturexxxxLocal dayxxxOld meteorological day
min_temperature_12h°CMinimum temperature within 12 hoursx -  -  - -x -  - Old meteorological day
no_cold_daysno. of daysNumber of cold days (minimum temperature < -10 °C)x -  -  - - -  - xOld meteorological day
no_frost_daysno. of daysNumber of days with frost (minimum temperature < 0°C)x -  - xLocal day -  - xOld meteorological day
no_tropical_nightsno. of daysNumber of tropical nights (minimum temperature > 20°C)x -  - xLocal day -  -  - -
acc_heating_degree_days_17no. of daysAccumulated heating degree days (17°C - mean_temp) (Danish: graddage - Danmark)x - xxLocal day -  -  - -
acc_heating_degree_days_19no. of daysAccumulated heating degree days (19°C - mean_temp) (Danish: graddage - Grønland)x -  -  - - - xxOld meteorological day
mean_relative_hum%Mean relative humidityxxxxLocal dayxxxOld meteorological day
max_relative_hum%Maximum relative humidityx - xxLocal day - xxOld meteorological day
min_relative_hum%Minimum relative humidityx - xxLocal day - xxOld meteorological day
mean_vapour_pressurehPaMean vapour pressurex -  -  - - - xxOld meteorological day
mean_wind_speedm/sMean wind speedxxxxLocal dayxxxOld meteorological day
max_wind_speed_10minm/sMaximum wind speed (10 minutes average)xxxxLocal day - xxOld meteorological day
max_wind_speed_3secm/sMaximum wind speed (3 seconds average)xxxxLocal dayxxxOld meteorological day
no_windy_daysno. of daysNumber of windy days (mean wind speed >= 10.8m/s)x -  - xLocal day -  - xOld meteorological day
no_stormy_daysno. of daysNumber of stormy days (mean wind speed >= 20.8m/s)x -  - xLocal day -  - xOld meteorological day
no_days_w_stormno. of daysNumber of days with storm (mean wind speed >=24.5m/s)x -  - xLocal day -  - xOld meteorological day
no_days_w_hurricaneno. of daysNumber of days with hurricane (mean wind speed >=28.5m/s)x -  - xLocal day -  - xOld meteorological day
mean_wind_dir_min0degreesMean wind direction (10 minutes average) at minute 0x -  -  - -x -  - Old meteorological day
mean_wind_dirdegreesMean wind directionxxxxLocal dayxxxOld meteorological day
mean_pressurehPaMean pressurexxxxLocal dayxxxOld meteorological day
max_pressurehPaMaximum pressurex -  -  - - - xxOld meteorological day
min_pressurehPaMinimum pressurex -  -  - - - xxOld meteorological day
bright_sunshineminutes/hoursMinutes/hours of bright sunshine.
For hourly time resolution the unit is minutes, for all other time resolutions the unit is hours.
xxxxLocal day----
mean_radiationW/m^2 / MJ/m^2Mean radiation (spectral range: 305-2800nm)
For hourly time resolution the unit is W/m^2, for all other time resolutions the unit is MJ/m^2.
xxxxLocal dayxxxOld meteorological day
acc_precipmmAccumulated precipitationxxxxLocal dayxxx

If it's a manual precipitation station: manual precipitation day

Else: old meteorological day

max_precip_24hmmMaximum 24-hour precipitation with associated datex -  - xLocal day -  - x

If it's a manual precipitation station: manual precipitation day

Else: old meteorological day

acc_precip_past12hmmAccumulated precipitation during the past 12 hoursx -  -  - -x -  - Old meteorological day
no_days_acc_precip_01no. of daysNumber of days with accumulated precipitation >= 0.1mmx -  - xLocal day -  - x

If it's a manual precipitation station: manual precipitation day

Else: old meteorological day

no_days_acc_precip_1no. of daysNumber of days with accumulated precipitation >= 1mmx -  - xLocal day -  - x

If it's a manual precipitation station: manual precipitation day

Else: old meteorological day

no_days_acc_precip_10no. of daysNumber of days with accumulated precipitation >= 10mmx -  - xLocal day -  - x

If it's a manual precipitation station: manual precipitation day

Else: old meteorological day

acc_precip_past24hmmAccumulated precipitation during the past 24 hoursx -  -  -  - x -  - Old meteorological day
max_precip_30mmmMaximum 30 minutes intensity in 24 hours with datex - xxThe exeption to the rule -  -  - Old meteorological day
no_days_snow_coverno. of days

Number of days with snow cover (> 50% covered)

x -  - xLocal day -  -  - Old meteorological day
mean_cloud_cover%The fraction of the sky covered by cloud of any type or height above the ground (see also Codes (climatedata))x - - --xxxOld meteorological day
no_clear_daysno. of daysNumber of clear days (mean cloud cover < 20%)x -  - -- - xxOld meteorological day
no_cloudy_daysno. of daysNumber of cloudy days (mean cloud cover > 80%)x -  - -- - xxOld meteorological day
max_snow_depthcmMaximum snow depth with date and locationx -  - xLocal day -  -  - Local day
snow_depthcmSnow depthx - x - Old meteorological day -  -  - -
snow_cover%Snow coverx - x - Old meteorological day -  -  - -
temp_grass *°CAir temperature measured at grass height (5-20 cm over terrain)-xx - Local day -  -  - -
temp_soil_10 *°CTemperature measured at a depth of 10 cm-xx - Local day -  -  - -
temp_soil_30 *°CTemperature measured at a depth of 30 cm-xx - Local day -  -  - -
leaf_moisture *minutesLeave moisture -xx - Local day -  -  - -
vapour_pressure_deficit_mean *kPaVapour Pressure Deficit Mean -xx-Local day -  -  - -

* The last 5 parameters in the table above are additional parameters, which are not quality controlled by DMI's climatologists. As a result, data can be erronous. 

** Read more about the different types of days here.

Parameters for 10x10km, 20x20km, municipality values, and country values





10x10km and 20x20km gridMunicipality and country
NameUnitDescriptionQC performed by DMI's climatologistsHourlyDailyMonthly and yearlyHourlyDailyMonthly and yearlyType of day**
mean_temp°CMean temperaturexxxxxxxLocal day
mean_daily_max_temp°CMean of daily maximum temperaturex - - -xxLocal day
max_temp_w_date°CMaximum temperature with associated datexxx -xx -Local day
no_ice_daysno. of daysNumber of ice days (maximum temperature < 0°C)x -x -x -Local day
no_summer_daysno. of daysNumber of summer days (maximum temperature > 25°C)x -x - -x -Local day
mean_daily_min_temp°CMean of daily minimum temperaturex - - -x -Local day
min_temp°CMinimum temperaturexxxxxxxLocal day
no_cold_daysno. of daysNumber of cold days (minimum temperature < -10 °C)x - -x -xLocal day
no_frost_daysno. of daysNumber of days with frost (minimum temperature < 0°C)x -x -xxLocal day
no_tropical_nightsno. of daysNumber of tropical nights (minimum temperature > 20°C)x -xx -xxLocal day
acc_heating_degree_days_17no. of daysAccumulated heating degree days (17°C - mean_temp)xxx -xxLocal day
mean_relative_hum%Mean relative humidityxxxxxxxLocal day
drought_index
Drought indexxxx -xxLocal day

pot_evaporation_makkink


Potential evaporation (Makkink)x-xx -xxLocal day
pot_evaporation_penman
Potential evaporation (Penman)xxx -xxLocal day
mean_wind_speedm/sMean wind speedxxxxxxxLocal day
max_wind_speed_10minm/sMaximum wind speed (10 minutes average)xxxxxxxLocal day
max_wind_speed_3secm/sMaximum wind speed (3 seconds average)xxxxxxxLocal day
mean_wind_dirdegreesMean wind directionxxxxxxxLocal day
mean_pressurehPaMean pressurexxxxxxxLocal day
bright_sunshineminutes/hoursMinutes/hours of bright sunshine.
For hourly time resolution the unit is minutes, for all other time resolutions the unit is hours.
xxxxxxxLocal day
mean_radiationW/m2 / MJ/m2Mean radiation (spectral range: 305-2800nm)
For hourly time resolution the unit is W/m2, for all other time resolutions the unit is MJ/m2.
xxxxxxxLocal day
acc_precipmmAccumulated precipitationxxxxxxxLocal day
no_days_acc_precip_01no. of daysNumber of days with accumulated precipitation >= 0.1mmx -xxxxLocal day
no_days_acc_precip_1no. of daysNumber of days with accumulated precipitation >= 1mmx -xx -xxLocal day
no_days_acc_precip_10no. of daysNumber of days with accumulated precipitation >= 10mmxxx -xxLocal day
max_precip_30mmmMaximum 30 minutes intensity in 24 hoursx -xx -xxThe exeption to the rule
mean_cloud_cover%Mean cloud cover-xxxxxxLocal day
snow_depthcmSnow depthx -xxxxOld meteorological day
temp_grass *°CAir temperature measured at grass height (5-20 cm over terrain)-xxxxxxLocal day
temp_soil_10 *°CTemperature measured at a depth of 10 cm-xxxxxxLocal day
temp_soil_30 *°CTemperature measured at a depth of 30 cm-xxxxxxLocal day
leaf_moisture *minutesLeave moisture (in danish: bladfugt)-xxxxxxLocal day
vapour_pressure_deficit_mean *
Vapour Pressure Deficit Mean (in danish: mætningsdeficit)-xxxxxxLocal day

* The last 5 parameters in the table above are additional parameters, which are not quality controlled by DMI's climatologists. As a result, data can be erronous. 

** Read more about the different types of days here.

Calculation Method for stationValue Parameters

In the table below, the calculation method for stationValue parameter values is described for the available time resolutions. In case of differences between Denmark and Greenland, these differences can be seen in the table below.


Calculation Method for stationValue Parameters
NameHourlyDailyMonthly and yearlymetObs parameter data is based on
mean_tempderived directly (see column 'metObs parameter data is based on')average of all hourly values within a dayaverage of all the underlying daily values

DNK: temp_mean_past1h


GRL: temp_mean_past1h or alternatively temp_dry at minute 0

mean_daily_max_temp- - average of all the underlying daily values of max_temp_w_date-
max_temp_w_datederived directly (see column 'metObs parameter data is based on')

DNK:
the highest of all the hourly values in the course of the day


GRL:
the highest of all the hourly values in the course of the day. If max_temp_w_date is not available max_temp_12h is used. If neither is available the highest value of mean_temp is used

the highest of the underlying daily values


if more than one identical highest value is found, the date is found as follows:

Jan-Jun: first found date
Jul-Dec: last found date

temp_max_past 1h
max_temp_12hderived directly (see column 'metObs parameter data is based on') -  - temp_max_past12h
no_ice_days -  - number of days where max_temp_w_date is below 0°C-
no_summer_days -  - number of days where max_temp_w_date is more than 25°C-
mean_daily_min_temp -  - average of the underlying daily values of min_temp-
min_tempderived directly (see column 'metObs parameter data is based on')

DNK:
the lowest of all hourly values of min_temp in the course of a day


GRL:
the lowest of all hourly values of min_temp in the course of the day. If min_temp is not available min_temperture_12h is used. If neither is available, the lowest value of mean_temp is used

the lowest of the underlying daily values

if more than one identical lowest value is found, the date is found as follows:

Jan-Jun: last found date
Jul-Dec: the first found date

temp_min_past1h
min_temperture_12hderived directly (see column 'metObs parameter data is based on')--temp_min_past12h
no_cold_days -  - number of days where min_temp is less than -10°C-
no_frost_days -  - number of days where min_temp is less than 0°C-
no_tropical_nights -  - number of days where min_temp is more than 20°C-
acc_heating_degree_days_17 - calculated as follows: 17°C minus the daily value of mean_tempsum of the underlying daily values-
acc_heating_degree_days_19 -calculated as follows: 19°C minus the daily value of mean_tempsum of the underlying daily values-
mean_relative_hum

DNK:
average of the 6 underlying values within the the hour


GRL:
derived directly (see column 'metObs parameter data is based on')

average of all hourly values within a dayaverage of the underlying daily values

DNK: humidity


GRL: humidity_past1h or alternatively humidity at minute 0

max_relative_hum - the highest of all hourly values of mean_relative_hum within a daythe highest of all the daily values-
min_relative_hum - the lowest of all hourly values of mean_relative_hum within a daythe lowest of all the daily values-
mean_vapour_pressure - see description of calculation method belowaverage of the underlying daily values -
mean_wind_speedaverage of the 6 underlying values within the houraverage of all hourly values within a dayaverage of the underlying daily valueswind_speed
max_wind_speed_10min

the highest of the 6 underlying values within the hour of the parameters in the column 'metObs parameter data is based on'

the highest of all hourly values within a daythe highest of all of the underlying daily values. If more than one identical highest values is found, the date is found as the latest datewind_speed & wind_max_per10min_past1h
max_wind_speed_3sec

DNK:
see description of calculation method below 


GRL:
derived directly (see column 'metObs parameter data is based on')

the highest of all hourly values within a daythe highest of all the underlying daily values. If more than one identical highest values is found, the date is found as the latest date

DNK:
wind_gust_always_past1h, wind_max, wind_gust_past10min_wind_gust_last1h, wind_speed


GRL:
wind_gust_always_past1h or alternatively wind_max at minute 0

no_windy_days -  - number of days where max_win_speed_10min is greater or equal to 10.8 m/s-
no_stormy_days -  - number of days where max_win_speed_10min is greater or equal to 20.8 m/s-
no_days_w_storm -  - number of days where max_win_speed_10min is greater or equal to 24.5 m/s-
no_days_w_hurricane -  - number of days where max_win_speed_10min is greater or equal to 28.5 m/s-
mean_wind_dir_min0derived directly (see column 'metObs parameter data is based on') -  - wind_dir at minute 0
mean_wind_dir

derived directly (see column 'metObs parameter data is based on')


mean of componentsmean of components

DNK: wind_dir_past1h

GRL: wind_dir_past1h or alternatively wind_dir at minute 0

mean_pressure

DNK:
average of the 6 underlying values within the hour


GRL:
derived directly (see column 'metObs parameter data is based on')

average of all hourly values within a dayaverage of the underlying daily values

DNK: pressure_at_sea

GRL: pressure_at_sea at minute 0

max_pressure - highest hourly value of mean_pressure within a daythe highest of all the underlying daily values-
min_pressure - 

lowest hourly value of mean_pressure within a day

the lowest of all the underlying daily values-
bright_sunshinederived directly (see column 'metObs parameter data is based on')sum of all underlying hourly values within a day, where minutes is converted to hours by dividing the sum of hourly values with 60sum of the underlying daily valuessun_last1h_glob
mean_radiationderived directly (see column 'metObs parameter data is based on')sum of all underlying hourly values of bright_sunshine within a day. In order to convet to MJ/m^2, the sum is multiplied by (60*60/10^6)sum of the underlying daily valuesradia_glob_past1h
acc_precipderived directly (see column 'metObs parameter data is based on')sum of all underlying hourly values within a daysum of the underlying daily valuesprecip_past1h
max_precip_24h -  - the highest of the underlying daily values of acc_prepic. If more than one identical highest values is found, the date is found as the latest date
acc_precip_past12hderived directly (see column 'metObs parameter data is based on') -  - precip__past12h
no_days_acc_precip_01 -  - number of days where acc_precip is greater or equal to 0.1 mm
no_days_acc_precip_1 -  - number of days where acc_precip is greater or equal to 1 mm
no_days_acc_precip_10 -  - number of days where acc_precip is greater or equal to 10 mm
acc_precip_past24hderived directly (see column 'metObs parameter data is based on') -  - precip_past24h
max_precip_30m - is found by inspecting the period from 23:31 local time to the previous day to 24.00 local time of the respective daythe highest of the underlying daily values of acc_prepic. If more than one identical highest value is found, the date is found as the latest date
no_days_snow_cover -  - number of days where snow_depth is greater than 0 and snow_cover is greater than 50
mean_cloud_cover

derived directly (see column 'metObs parameter data is based on')

average of the underlying hourly values provided that there has to be at least 12 hourly values and there are not more than 2 hourly values missing in a rowaverage of the underlying daily valuescloud_cover at minute 0
no_clear_days - 

= 1 if mean_cloud_cover is less than 20%

= 0 if mean_cloud_cover is greater than or equal to 20%

number of days where  mean_cloud_cover is less than 20%
no_cloudy_days - 

=1 if mean_cloud_cover is greater than 80%,

= 0 if mean_cloud_cover is less than or equal to 80%

number of days where mean_cloud_cover is greater than 80%
max_snow_depth -  - the highest of the underlying daily values of snow_depth. If more than one identical highest values are found, the date is found as the latest date
snow_depth - 

derived directly (see column 'metObs parameter data is based on'), but code -1 is changed to 0,5 cm and code -2 is changed to 0 cm

 - snow_depth_man
snow_cover - derived directly (see column 'metObs parameter data is based on'), but codes are changed to % - snow_cover_man
temp_grassderived directly (see column 'metObs parameter data is based on')average of all hourly values within a day - temp_grass_mean_past1h
temp_soil_10derived directly (see column 'metObs parameter data is based on')average of all hourly values within a day - temp_soil_mean_past1h
temp_soil_30derived directly average of all hourly values within a day - N/A 
leave_moisturederived directly (see column 'metObs parameter data is based on')average of all hourly values within a day - leav_hum_dur_past1h
vapour_pressure_deficit_mean

see description of calculation method below 

average of all hourly values within a day

-

temp_mean_past1h and humidity

Calculation method of mean_vapour_pressure (daily value)

The mean_vapour_pressure is calculated from the hourly values of mean_temp and mean_relative_hum. For every of the days hourly value, where temperature (tt) and relative humidity (rh) is available, the mean_vapour_pressure (vp) is calculated using the following formula:

If tt = 0, then vp = 6.107 * rh / 100

If tt < 0, then

   a = 9.5
   b = 265.5
   q = a * tt / (tt + b)
   vp = 6.107 *10q * rh / 100

If tt > 0, then
   a = 7.5
   b = 237.3
   q = a * tt / (tt + b)
   vp = 6.107 *10q * rh / 100

The daily value of mean_vapour_pressure is calculated as a mean of the hourly values, which could be calculated within the day.


Calculation method for max_wind_speed_3sec

max_wind_speed_3sec is found in a 24 hour time interval from 00 to 24 local. In this interval the observation at 00:00 is not included in the calculation, but the observation at 24:00 is included in the calculation. 


Time period24 hours ( 00:00-24:00) local time
Examination period24 hours ( 00:00-24:00) local time
ConditionIn order for at station to be included in the calculation of max_wind_speed_3sec, the number of 10 minute wind speeds (wind_speed) in the time period must be greater than 140
OutputFor every grid cell the higest max:_wind_speed_3sec
Calculation

The calculation is based on station values, so that the highest 3-second wind is found for each station. There are several parameters which determine the 3-second wind speed, where the following priority is used:

  1. wind_max or wind_gustallways_past1h
  2. wind_gust_past10min or wind_gust_last1h

If none of the above parameters with first or second priority are available for the station in the desired time interval, the max_wind_speed_3sec is estimated from the highest wind_speed the time interval.

Calculation method for vapour_pressure_deficit_mean

The vapour_pressure_deficit_mean is calculated from the hourly values of mean_temp and mean_relative_hum. The daily value of mean_vapour_pressure is calculated as a mean of the hourly values, which could be calculated within the day.

                     

If mean_temp > 0 then,

            SatVapPres = 0.611 * Math.exp (17.27 * mean_temp / (mean_temp + 237.3))


If mean_temp <= 0 then,

            SatVapPres = 0.611 * Math.exp(21.87 * mean_temp / (mean_temp + 265.5))

           

VPD = SatVapPres * (100 – mean_relative_hum) / 100

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