knmy - A simple Python wrapper for Dutch weather data from KNMI Documentation Status

knmy is a Python package for downloading and processing weather data from the automated weather stations of the Dutch Meteorological Institute (KNMI). Documentation of the used API can be found here (only in Dutch).


The main function is get_knmi_data(), which requires at minimum a type (first argument) to function. You can choose from:

  1. type = 'daily', which returns the daily aggregate weather data of all selected weather variables.
  2. type = 'hourly', which returns the hourly aggregate weather data of all selected weather variables.
  3. type = 'daily_rain', which always returns only the daily rain and snow cover data.

For convenience you have access to three wrapper functions that correspond to each of the aforementioned types: get_daily_data(), get_hourly_data() and get_daily_rain_data()

Example usage

from knmy import knmy

# Return daily aggregated wind, temperature and sunshine duration data for station 209 (IJmond) for the 1st til
# 6th of January, 2017
knmy.get_daily_data(stations=[209], start=20170101, end=20170106, variables=['WIND','TEMP', 'SQ'])

# Return dataframe with hourly wind and temperature data for station 209 (IJmond) and 235 (De Kooy) for the 1st
# til 6th of January of the years 2015 til 2017 for the 8th til 20th hour of the day
disclaimer, stations, variables, data = knmy.get_hourly_data(stations=[209, 235], start=2015010108, end=2017010620,
                                                             inseason=True, variables=['WIND', 'TEMP'], parse=True)

# Return dataframe with daily rain data for all stations for January 1st, 2017
disclaimer, variables, data = knmy.get_daily_rain_data(start=20170101, end=20170101, parse=True)

Function parameters

stations should contain a list of weather station numbers. To find out which weather stations are available for use, use the function without setting any stations (but with a start and end set), the function will then return a variable stations which contains a list of stations for which data is available for that period.

start and end are either an integer or datetime object ( for get_daily_data and datetime.datetime for get_hourly_data. If hourly data is requested, data is always returned starting from the hour set in start until the hour set in end. In case an integer is provided, make sure the first hour of the day (00:00-01:00) is hour 1 and the last hour of the day (23:00-24:00) is hour 24. To request overnight data — such as from 22:00 til 06:00 the next morning — use for example start=2017010123 and end=2017010507.

variables should contain a list of variables, and if none are specified returns all recorded variables. Variables can be selected individually, but also in the groups below. If you are unsure of the available variables, use one of the functions without providing variables and read the unpacked list of variables (see Example usage).

Variable groups:

  • ALL = All variables (Default)
  • TEMP = TG:TN:TX:T10N Temperature
  • SUNR = SQ:SP:Q Sunshine
  • PRCP = DR:RH:EV24 Precipitation and potential evaporation
  • PRES = PG:PGX:PGN Pressure at sea level
  • VICL = VVN:VVX:NG Visibility and cloud cover
  • MSTR = UG:UX:UN Humidity

inseason is a boolean. If set to True, the function will only return data within the month-date combination for all given years (see Example usage).

parse is a boolean. If set to True, the function will parse the KNMI output data and return a disclaimer, measured variables, data and a list of stations.