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Yearly Accumulated Day Counts

These parameters represent the number of days that fulfil a certain condition since the 1st of January of the queried year.

Temperature Dependent | Precipitation Dependent

Temperature Dependent

Below is an overview of all temperature dependent parameters:

Vegetation Days | Heating Days | Heating Degree Days | Cooling Degree Days | Desert Days | Hot Days | Summer Days | Tropical Nights | Frost Days | Ice Days

Every parameter is now explained in more detail:

Vegetation Days

This parameter returns the number of vegetation days (days on which the mean temperature was above 5°C) since the 1st of January.

vegetation_days:d

Examples

  • Show the number of vegetation days for 35 days after the 10th of February.

    https://api.meteomatics.com/2025-04-23T00:00:00ZP35D:P1D/vegetation_days:d/47.412164,9.340652/html

    Vegetation days

  • To obtain the data in a different output format, just replace the format parameter in the URL by one of the following: csv, json, xml, png, html, netcdf.
    Here is an example for the json format:

    https://api.meteomatics.com/2025-04-23T00:00:00ZP10D:P1D/vegetation_days:d/47.412164,9.340652/json

    {"version":"3.0","user":"api-test","dateGenerated":"2017-08-25T08:38:48Z","status":"OK","data":
[{"parameter":"vegetation_days:d","coordinates":[{"lat":47.4122,"lon":9.34065,"dates":
[{"date":"2017-03-10T00:00:00Z","value":11},{"date":"2017-03-11T00:00:00Z","value":12},
{"date":"2017-03-12T00:00:00Z","value":13},{"date":"2017-03-13T00:00:00Z","value":14},
{"date":"2017-03-14T00:00:00Z","value":15},{"date":"2017-03-15T00:00:00Z","value":16},
{"date":"2017-03-16T00:00:00Z","value":17},{"date":"2017-03-17T00:00:00Z","value":18}]}]}]}

Heating Days

This parameter returns the number of heating days (days for which the 24h-mean is less than 15°C, or the number of days buildings need to be heated) since the 1st of January.

heating_days:d

Heating Degree Days

Heating degree days (HDD) is a measurement designed to quantify the energy demand for heating a building. This parameter returns the accumulated difference in °C between the daily mean temperature and a configurable base temperature, if the daily mean temperature is below that base temperature, since the 1st of January or on a daily base (daily heating degree days).

heating_degree_days:hdd

heating_degree_days_base_<base_temperature><unit>:hdd

daily_heating_degree_days:hdd

daily_heating_degree_days_base_<base_temperature><unit>:hdd

Available base temperatures: continuous between 0°C to 30°C, not including 0 and 30.

Available units for base temperature: C, F, K.

The unit of the base temperature needs to be specified as well, so for a base temperature of 20 °C, the parameter would be: heating_degree_days_base_20C:hdd. The default is 15°C. The unit of the output is in hdd, but it will be calculated based on the unit the base temperature is specified in. If another unit is specified than C, the base tempertaure still needs to be within 0 to 30°C, so for example, 31F won't work since it's less than 0°C.

Cooling Degree Days

Cooling degree day (CDD) is a measurement designed to quantify the energy demand for cooling a building. This parameter returns the accumulated difference in °C between the daily mean temperature and a configurable base temperature, if the daily mean temperature is above that base temperature, since the 1st of January or on a daily base.

cooling_degree_days:cdd

cooling_degree_days_base_<base_temperature><unit>:cdd

daily_cooling_degree_days:cdd

daily_cooling_degree_days_base_<base_temperature><unit>:cdd

Available base temperatures: continuous between 0°C to 30°C, not including 0 and 30.

Available units for base temperature: C, F, K.

The unit of the base temperature needs to be specified as well, so for a base temperature of 20 °C, the parameter would be: cooling_degree_days_base_20C:cdd. The default is 15°C. The unit of the output is in cdd, but it will be calculated based on the unit the base temperature is specified in. If another unit is specified than C, the base tempertaure still needs to be within 0 to 30°C, so for example, 31F won't work since it's less than 0°C.

Desert Days / Extremely Hot Days

This parameter returns the number of extremely hot days (days on which the maximum temperature at 2m exceeds 35°C) since the 1st of January.

desert_days:d

Examples

Hot Days

This parameter returns the number of hot days (days for which the 24-hour maximum temperature was greater than 30°C) since the 1st of January.

hot_days:d

Examples

Summer Days

This parameter returns the number of summer days (days for which the 24-hour maximum temperature was greater than 25°C) since the 1st of January.

summer_days:d

Examples

Tropical Nights

This parameter returns the number of tropical nights (days for which the 24-hour minimum temperature was greater than 20°C) since the 1st of January.

tropical_nights:d

Examples

Frost Days

This parameter indicates the count of frost days, which are days when the temperature fell below 0 degrees Celsius, since the 1st of January. The count of frost days corresponds to the count of freezing days in the United States.

frost_days:d

Examples

  • Show the number of frost days from the 10th of January on for a period of 35 days.

    https://api.meteomatics.com/2025-04-23T00:00:00ZP35D:P1D/frost_days:d/47.412164,9.340652/html

    Frost days

  • Show the number of frost days from the 10th of April on for a period of 15 days.

    https://api.meteomatics.com/2025-04-23T00:00:00ZP15D:P1D/frost_days:d/47.412164,9.340652/json

    {"version":"3.0","user":"api-test","dateGenerated":"2018-02-14T15:53:19Z","status":"OK","data":
[{"parameter":"frost_days:d","coordinates":[{"lat":47.4122,"lon":9.34065,"dates":
[{"date":"2017-04-10T00:00:00Z","value":31},{"date":"2017-04-11T00:00:00Z","value":31},
{"date":"2017-04-12T00:00:00Z","value":31},{"date":"2017-04-13T00:00:00Z","value":31},
{"date":"2017-04-14T00:00:00Z","value":31},{"date":"2017-04-15T00:00:00Z","value":31},
{"date":"2017-04-16T00:00:00Z","value":31},{"date":"2017-04-17T00:00:00Z","value":31},
{"date":"2017-04-18T00:00:00Z","value":31},{"date":"2017-04-19T00:00:00Z","value":31},
{"date":"2017-04-20T00:00:00Z","value":32},{"date":"2017-04-21T00:00:00Z","value":33},
{"date":"2017-04-22T00:00:00Z","value":33},{"date":"2017-04-23T00:00:00Z","value":33},
{"date":"2017-04-24T00:00:00Z","value":33},{"date":"2017-04-25T00:00:00Z","value":33}]}]}]}

Ice Days

This parameter returns the number of ice days (days for which the 24-hour maximum temperature was less than 0°C) since 1st of January.

ice_days:d

Examples

Precipitation Dependent

Below is an overview of all precipitation dependent parameters:

Rain Days | Heavy Rain Days | Dry Days

Every parameter is now explained in more detail:

Rain Days

This parameter returns the number of rain days (days on which at least 0.1 mm of rain fell) since 1st of January.

rain_days:d

Examples

Heavy Rain Days

heavy_rain_days:d

This parameter returns the number of heavy rain days (days for which the precipitation sum was greater than 10mm) since 1st of January.

Examples

Dry Days

This parameter returns the number of dry days since 1st of January.

dry_days:d

Examples