Weather API in Detail

Current conditions: data from the closest relevant weather observation station which has recently reported data

    If there are no recent observations within 100 km of the given coordinates, current conditions will not be reported.
    Vaisala provides complimentary gif/png images for visualization of weather codes.
   
Current condition parameters as reported by the station

•         observation station name - e.g. "London Heathrow"
•         distance - distance to the observations station from the chosen location e.g. "8 km NE"
•         observation time - the time the observation was made in local time
•         the temperature in Celsius or Fahrenheit
•         the feels-like temperature in Celsius or Fahrenheit
•         graphical symbol code - e.g. "d420"
•         wind speed in m/s, knots, km/h or miles/h
•         wind direction (N, NE, E, ...)
•         pressure in hPa, e.g. "1012"
•         relative humidity in percentages, e.g. "87"
•         visibility in meters, e.g. "10000" for 10 km

Detailed short forecasts: contain intra-day details for several time steps

•     Available with one hour, 3-hourly, 6-hourly intervals
•     Vaisala provides complimentary gif/png images for visualization of weather codes
•     Recommended forecast length up to two days

Daily overview forecasts: contain summary data for one day

•     Recommended forecast length up to seven days
•     Vaisala provides complimentary gif/png images for visualization of weather codes
•     Weather parameters limited to:
  • graphical symbol code
  •  min/max temperature in Celsius or Fahrenheit

API query for a two day forecast

https://HOST/data?lon=24.97&lat=60.32&ftimes=48/24h&tz=Europe/Helsinki&format=json/[YOUR-API-KEY]

API response

	
    {
        "loc": [
            {
                "obs":{
                    "station":"Helsinki Kumpula",
                    "dist":"2 km S",
                    "dt":"2020-10-22 09:20:00",
                    "t":"9",
                    "tf":"7",
                    "s":"d410",
                    "wn":"SE",
                    "ws":"5",
                    "p":"998.5",
                    "rh":"97",
                    "v":"6610"
                 },
                "fc": [
                    {
                        "dt":"2020-10-22",
                        "s":"d430",
                        "tx":"11",
                        "tn":"8",
                        "pr": "14.83",
                        "wsx":"6"
                    },
                    {
                        "dt":"2020-10-23",
                        "s":"d220",
                        "tx":"11",
                        "tn":"1",
                        "pr": "5.91",
                        "wsx":"6"
                    }
                ]
            }
        ]
    }
  

API query for a two hour forecast

https://HOST/data?lon=24.97&lat=60.32&ftimes=2/1h&tz=Europe/Helsinki&format=json/[YOUR-API-KEY]

API Response

		{
			"loc":[
				{
					"obs": {
						"station":"Helsinki-Vantaa",
						"dist":"1 km NW",
						"dt":"2020-10-22 09:49:00",
						"t":"9",
						"tf":"6",
						"s":"d430",
						"wn":"SE",
						"ws":"5",
						"p":"998.2",
						"rh":"98",
						"v":"3879"
		 			},
					"fc": [
						{
							"dt":"2020-10-22 10:00",
							"s":"d430",
							"t":"8",
							"tf":"5",
							"ws":"5",
							"wn":"S",
							"pp":"99",
							"pr":"2.06"
							
						},
						{
							"dt":"2020-10-22 11:00",
							"s":"d430",
							"t":"8",
							"tf":"6",
							"ws":"5",
							"wn":"S",
							"pp":"99",
							"pr":"2.45"
						}
					]
				}
			]
		}

It is possible to request for example hourly and daily forecast in one API call. The following request

http://HOST/data?lon=24.97&lat=60.22&ftimes=24/1h,120/24h&format=json/[YOUR_API_KEY]&tempunit=C&windunit=MS

is responded with the hourly forecast for the next 24 hours and a daily forecast for the next 5 days. In response these forecast intervals are found under separate json keys (fc1,fc2,...).

API query to search locations

https://HOST/search?q=new%20york&format=json/[YOUR-API-KEY]

API Response

	
		{
			"searchresults": {
				"query":"new york",
				"loc": [
					{
						"id":"105128581"
						"name":"New York City",
						"country":"United States",
						"tz":"America\/New_York",
						"lon":"-74.005973816","lat":"40.714267731"},
						{
							"id":"105128616",
							"name":"New York Mills",
							"country":"United States",
							"tz":"America\/New_York",
							"lon":"-75.291275024",
							"lat":"43.105346680"
						},
						{
							"id":"105039192",
							"name":"New York Mills",
							"country":"United States",
							"tz":"America\/North_Dakota\/Center",
							"lon":"-95.376144409",
							"lat":"46.518016815"
					}
				]
			}
		}
	

Pick the location from the result list and use its "id" to request weather data for the location:

http://HOST/data?l=105128581&ftimes=48/24h&format=json/[YOUR_API_KEY]&tempunit=C&windunit=MS&tz=

• lon - the longitude of the location, in decimal degrees
• lat - the latitude of the location, in decimal degrees

or

• id - Vaisala location id
• format - reply format, Each customer is provided a dedicated format name, "json/standardfeed" and "xml/standardfeed" are used as examples above. Custom formats can be created.

•     alt - altitude above sea level in meters, e.g. "2148" for 2148 meters. By default, the altitude is estimated from the numerical weather prediction (NWP) model value for the given coordinates, which can cause errors in mountain regions. Providing the actual altitude will enable the Weather API forecast engine to make better temperature predictions in locations with large height variations. On level ground, the benefit will be negligible.
•     tempunit - either "C" or "F" for Celsius or Fahrenheit, defaults to Celsius
•     windunit - either "MS", "KTS", "KMH", or "MPH" for m/s, knots, km/h or miles/h, defaults to m/s
•     tz - POSIX formatted time zone string for response timestamps, e.g. "UTC", or "Europe/Helsinki". If not given, time zone is approximated from coordinates, which can result in errors near time zone borders.
•     ftimes - (only standard/premium packages) length/step-interval of the requested forecast in hours, 24h interval switches on the daily overview mode. E.g. "72/24h" returns daily overview for the next three days, "48/3h" returns three-hourly forecasts for the next two days, and "12/1h" returns hourly forecasts for the next 12 hours. Recommended intervals are: 1, 3, 6, 24. The maximum forecast length is 10 days. Optionally the time of the first forecast can be given in the ftimes parameter, see below for details (*).

(*) using ftimes query parameter to specify the first timestep

There are two formats:

    ftimes=length/timestep
    ftimes=length/timestep/firststep

Format 1 uses default values for deciding the time of the first forecast. In format 2 the first step parameter modifies the time of the first forecast. For daily summary forecasts (of type x/24h) it is interpreted as the number of hours before midnight, default is 11. For hourly forecasts it is interpreted as the minimum number of hours from now to the first forecast time step, default is 0. Examples:

    ftimes=72/24h - Default, 1 pm, i.e. switch the date at 13:00 o'clock
    ftimes=72/24h/11 - Same as default, switch the date at 13:00 o'clock, 11 hours before midnight
    ftimes=72/24h/3 - Switch the date at 9 pm (3 hours before midnight)
    ftimes=72/24h/0 - Switch the date at midnight
    ftimes=72/24h/-6 - Show yesterday's forecast until 6 am

    ftimes=12/1h - Default, hourly forecasts twelve hours forwards from now
    ftimes=12/1h/0 - Same as default, hourly forecasts with first-time step zero hours from now
    ftimes=12/1h/6 - Hourly forecasts for twelve hours, starting six hours from now, i.e. ending 18 hours from now

Please note that the time zone calculation for local time is approximate.

• dt - timestamp of the observation/forecast, for daily overview dt contains only the date part. Unless provided in the query parameters, for Weather API forecasts the time zone is an approximation, which may be inaccurate near time zone borders. When using Foreca IDs the time zone is accurate. For observations (the obs tag) the time is always in local time of the observation station.
• station - observation station name - e.g. "Berlin Tegelhof"
• dist - distance to the observations station from the given coordinates appended with wind direction in English, e.g. "8 km NE"
• p - pressure in hPa, e.g. "1012"
• v - visibility in meters, e.g. "10000" for 10 km
• t - air temperature (default unit: Celsius)
• tx - 24h maximum temperature (default unit: Celsius) (daily summary data)
• tn - 24h minimum temperature (default unit: Celsius) (daily summary data)
• tf - the so-called feels-like temperature (default unit: Celsius), which is the combined NOAA/NWS 'face only' wind chill index and Rothfusz heat index, which take into account the cooling and heating effects of wind and humidity
• rh - relative humidity in percentages, range from 0 to 100
• pp - the probability of precipitation in percentages, range from 0 to 100
• tp - the probability of thunder in percentages, range from 0 to 100
• pr - accumulated precipitation (default unit: millimeters). Exception: If 15 minute time steps are requested "pr" is the intensity of the rain (unit :millimeters / hour).
• ws - 10-minute average wind speed (default unit: m/s)
• wsx - daily maximum of the 10-minute average wind speed (default unit: m/s)
• wsa - daily average of the 10-minute average wind speed (default unit: m/s)
• wn - wind direction string, one of N, NE, E, SE, S, SW, W, NW
• s - symbol code (see explanations in https://corporate.foreca.com/en/resources/foreca-symbols)
• c - cloudiness, in percentages, range from 0 to 100
• ca - average cloudiness during the day in percentages, range from 0 to 100
• sT - symbol code as text, use the lang parameter to control output language
• rise - sunrise time in 24h clock notation in local time
• set - sunset time in 24h clock notation in local time
• UV - UV index based on the global ozone forecast model (1-2=low, 3-5=moderate, 6-7=high, 8-10=very high, 11+=extreme) NOTE: max 5 days forecast available
• dl - day length in minutes

Please note that Weather API may be upgraded with new data in the future. This means that your application must parse the response so that it does not break if the order of the parameters changes or new parameters appears.