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Returns the most recent observation from a station or set of stations

Request Format

A Latest request is an HTTP URL with the following form:


Acquiring data from this web service requires certain parameters. When encoding URLs, all parameters are separated using the ampersand (&) character and their value is indicated by an equal sign (=). Below is a list of accepted parameters.

  • token (required), Your application’s API token. This is used to identify who is requesting API data. You are never required to use multiple tokens, but you can use as many as you need. Learn more in our tokens overview.

Optional Parameters

  • Any number of station selection parameters (optional). Including no station selections will return results for all stations. This can result in extremely large results for services that support it.

Station Selection Parameters

These selectors individually or combined to target the desired stations.

Exclusion Operator

Selectors noted as (excludable) may be specified with a ! preceding a value to remove/exclude from the selection from a result set. So stid=!KSLC would prevent KSLC from returning in a query. This should be used in combination with different selectors. Remember to only include any given selector once.


(string, excludable), Single or comma separated list of SynopticLabs station IDs. Use a ! before any value to exclude matching stations. Example: stid=mtmet,kslc,fps. Try it Now


(string, excludable), Single or comma separated list of abbreviated 2 character states. If country is not included, default is United States (US). Use a ! before any value to exclude matching stations. Example: state=ut,wy,dc.


(string, excludable), Single or comma separated list of abbreviated 2 or 3 character countries. Use a ! before any value to exclude matching stations. Example: country=us,ca,mx.


(string, excludable), Single or comma separated list of National Weather Service Zones. Use a ! before any value to exclude matching stations. Example: nwszone=UT003,CA041.


(string, excludable), Single or comma separated list of National Weather Service Fire Zones. Use a ! before any value to exclude matching stations. Example: nwsfirezone=LOX241


(string, excludable), Single or comma separated list of National Weather Service County Warning Areas. Use a ! before any value to exclude matching stations. Example: cwa=LOX.


(string, excludable), Single or comma separated list of Geographic Area Coordination Centers. Use a ! before any value to exclude matching stations. Example: gacc=GB.


(string, excludable), Single or comma separated list of Sub Geographic Area Coordination Centers. Use a ! before any value to exclude matching stations. Example: subgacc=EB07.


(string, excludable), Single or comma separated list of counties. Use the state parameter to filter by state in the case of duplicate county names (i.e. “King”). Use a ! before any value to exclude matching stations. Example: county=king&state=wa.


(string), Single or comma separated list of sensor variables found here. The request will return all stations matching at least one of the variables provided. This is useful for filtering all stations that sense only certain variables, such as wind speed, or pressure. Do not specify vars twice in a query string. Some web services use this argument to adjust what information is delivered. Example: vars=wind_speed,pressure. Try it Now


(string), Define how &vars is understood. or (the default) means any station with any variable in the list is used. and means a station must report every variable to be included. Example: varsoperator=and.


(number, string, excludable), Single or comma separated list of network IDs or short names. The ID can be found be using the Networks service and are also listed here. Use a ! before any value to exclude specific networks from a result set. Example: network=153 or network=uunet,raws.


(string), A comma separated list of three values of the type [latitude,longitude,miles] or [stn_id,miles]. Coordinates are in decimal degrees. Returns all stations within radius of the point (or station, given by the station ID) and provides the DISTANCE of the station from given location with units of miles. Adding limit=n to the query will limit the number of returned stations to n stations, and will order the stations by DISTANCE. Some examples are: radius=41.5,-120.25,20, radius=wbb,10, radius=41.5,-120.25,20&limit=10.


(string), A bounding box defined by the lower left and upper right corners in decimal degrees latitude and longitude coordinates, in the form of [lonmin,latmin,lonmax,latmax]. Recall that for regions involving the western and southern hemispheres that the coordinates are negative values (e.g., 120 W is -120, 20 S is -20). Example: bbox=-120,40,-119,41.

Bounding Box Thinning

A new feature allows you to use the API to thin the returned station set within a bounding box by providing some additional arguments. These arguments only take effect when the bbox parameter is used:


(number) the height of the map viewport in pixels


(number) the width of the map viewport in pixels


(number) the preferred number of pixels a station on the map should consume


(numbers, comma-separated) a list of comma separated network IDs that will be considered in the order provided. When there is a collision of stations within the defined “spacing” area, any station matching the list of preferred networks will be shown over any other.


(string), A value of either active or inactive returns only stations that are currently set as active in the archive. By default, omitting this parameter will return all stations. Example: status=active.


(1, 0 [default]), A value of 1 or 0. When set to 1 an extended list of metadata attributes for each returned station is provided. This result is useful for exploring the zones and regions in which a station resides. Example: complete=1.


(string), Case-insensitive comma-separated list of metadata attributes to include in the output response. Default is to include all attributes. Only works with attributes defined in the default metadata set (e.g. attributes shown via complete=1 cannot be selected). Example: fields=stid,name.

  • obtimezone (UTC [default], local), Indicates if the time zone of the response is in UTC or the local timezone of the station. Sets the timezone applied to the observation output (input times associated with start and end are always UTC). Example: obtimezone=local. This parameter can’t be used with timeformat=%s.

  • showemptystations (off [default], on), Indicates if stations with no observations will be returned. Setting to on will return any station meeting the defined time period, variables, and geographic or network parameters, even if there are no observation data available.

  • units (metric [default], english, [custom format]), Defines the unit of measure for returned data. For standard measurements used by many in the United States english will fill most needs. There is also the ability to support custom unit configurations. This is achieved by accessing the variable group such as “temp” and setting the desired unit using a pipe (|) character. The following list describes the available units for each variable group.

    • temp (C, F, K), Temperature: Celsius, Fahrenheit and Kelvin.

    • speed (mps, mph, kph, kts), Speed/Velocity: Meters per second, miles per hour, kilometers per hour, knots.

    • pres (pa, mb, inhg), Pressure: Pascals, millibars, inches mercury.

    • height (m, ft), Height: Meters, feet.

    • precip (mm, cm, in), Precipitation: Millimeters, centimeters, inches.

    • alti (pa, inhg), Altimeter: Pascals, inches mercury.

    Furthermore, it is possible to modify one of the preset settings (metric/english). This is achieved by appending a variable group and unit to the parameter string with a comma. For example, to use “english” units with any speed variables in mph (instead of default knots) the parameter would be &units=english,speed|mph.

  • within, Restricts the response to observations within a time window previous to the current time in minutes (e.g. within=60 returns only observations within the last 60 minutes). By default, all latest observations are returned. Note that for stations that have stopped reporting or report infrequently, the latest observations could be days, months or years old.

  • minmax, Integer for number of days to show daily minimium and maximum values (up to 7 days previous to current day). Synoptic’s full suite of QC checks are applied to the raw data before calculating min and max values. The minmax arg is required to use this feature. Try it Now

  • minmaxtype, (UTC, local [default]), Controls whether min and max values are calculated using the station local day or the UTC day.

  • minmaxtimezone, (UTC, local), Controls whether the timestamps associated with the min and max values are returned in local or UTC timezone. (default matches the input to minmaxtype)

  • hfmetars (0, 1 [default]) Disable use of High Frequency NOAA METAR data. This is a variant of the hourly NWS/FAA airport data where observations are recorded approximately every 5 minutes. A value of 0 will exclude these data from data returns.

  • sensorvars (0 [default], 1) Indicates if sensor specific metadata for each variable in the SENSOR_VARIABLES element will be returned. Each sensor element contains the following: a position value indicating the height of the sensor, a PERIOD_OF_RECORD value that describes the period of the sensor being active, and a derived_from list of source observations (derived variables only). By default (0), empty objects will be returned within the SENSOR_VARIABLES element.

Response Format Parameters

  • timeformat, Defines a time format that all time stamps in the data response to be formatted to. By default the API will return time values in ISO 8601 format. This behavior can be changed by passing a string with a valid strftime expression. Below are some common examples.

    • timeformat=%m/%d/%Y at %H:%M would yield “06/22/2017 at 17:06”

    • timeformat=%b%20%d%20%Y%20-%20%H:%M would yield “Jun 22 2017 - 17:06”

    • timeformat=%s returns Unix/POSIX time in terms of seconds (this parameter cannot be used with obtimezone). This is a special function in addition to the supported strftime arguments.

  • output (json [default], xml, geojson), Indicates the response format of the request. It’s recommended to use the JSON format which there are well supported parsing libraries in all major languages. Try it Now

    • GeoJSON will only return the best guess sensor if the station has multiple sensors of the same type.

Data Checks and Quality Control

By default, the API does not return data that has been flagged as non-plausible by the Synoptic Range Check, e.g. a temperature value of 200°C.

If the qc parameter is omitted then the API will return data while assuming the following: qc=on, qc_remove_data=on, qc_flags=off and qc_checks=sl_range_check. Note that if the range check removes all values for all requested stations and variables, a response message of “No stations found for this request” will be returned. If the range check removes values only for certain variables, those variables will not be present in the OBSERVATIONS object.

Note: The existence of a data check flag for an observation is not necessarily an indication of invalid or inaccurate data. For a detailed explanation of data checks, please click here to read more.

  • qc (on [default], off), Indicates the application behavior of the QC attributes on the data requested. If set to off then all data will be returned without data checks and quality control (not recommended). If set to on, a QC_SUMMARY object is returned, a QC_FLAGGED: [bool] key will be inside the STATION object, and individual data checks will be in the qc response key for each variable within the OBSERVATIONS object.

  • qc_remove_data (on, off, mark), Indicates the response behavior for an observation that fails a user specified data check. (default on if qc parameter omitted, else off if qc=on)

    • off returns the data values even if a data check failure is present for that data.

    • on removes failed data values, returning null. If all values for all requested stations and variables are set to null, a response message of “No stations found for this request” will be returned. If the value for an individual variable is set to null, the variable will not be present in the OBSERVATIONS object.

    • mark replaces failed data with a value of false.

  • qc_flags (on, off), Indicates whether the data checks are returned alongside any data that failed a requested check. If on then the data checks will be returned in the qc response key for each variable within the OBSERVATIONS block. (default off if qc parameter omitted, else on if qc=on)

  • qc_checks ([flag name], [flag source], keyword), defines a list of applied data checks. (defaults to sl_range_check if qc parameter omitted, else synopticlabs if qc=on)

    • “flag name” allows targeting one or more specific data checks in a comma separated list (e.g. sl_range_check,sl_rate_check)

    • “flag source” allows targeting one or more data check providers (synopticlabs, mesowest or madis).

    • “keyword” can be one of the following: basic,advanced, all. Click here to read more about the basic and advanced groups of checks).all will apply all data checks in our system. Caution: This argument will enable all flag sources, some of which can aggressively flag data, and may remove significant amounts of data if qc_remove_data=on.

Some examples of modifying the default QC checks are:

  • qc_checks=synopticlabs,ma_range_check, Applies the Synoptic QC suite and MADIS range check

  • qc_checks=synopticlabs,madis, Applies the Synoptic and MADIS QC suites.

Request Response

JSON Format

The Latest service will return its results in a single organized and self describing JSON object. At a minimum, every request will return a JSON object with a "SUMMARY" field.

An example JSON response would be:

  UNITS: {
    solar_radiation: "W/m**2"
      1: "sl_range_check"
      1: "SynopticLabs"
    QC_NAMES: {
      1: "SynopticLabs Range Check"
      MNET_ID: "153",
        start: "1997-01-01T00:00:00Z",
        end: "2023-07-31T17:55:00Z"
      ELEVATION: "4806",
      NAME: "U of U William Browning Building",
      STID: "WBB",
        solar_radiation: { }
      ELEV_DEM: "4727.7",
      LONGITUDE: "-111.84755",
      UNITS: {
        position: "m",
        elevation: "ft"
      STATE: "UT",
        solar_radiation_value_1: {
          date_time: "2023-08-01T23:15:00Z",
          value: 576.2
      RESTRICTED: false,
      QC_FLAGGED: false,
      LATITUDE: "40.76623",
      TIMEZONE: "America/Denver",
      ID: "1"
    DATA_QUERY_TIME: "1.07908248901 ms",
    METADATA_RESPONSE_TIME: "62.3641014099 ms",
    DATA_PARSING_TIME: "0.0760555267334 ms",
    VERSION: "v2.21.0",
    TOTAL_DATA_TIME: "1.15704536438 ms",

    • NUMBER_OF_OBJECTS, (always returned) is a integer value of the number of stations returned.

    • RESPONSE_CODE, (always returned) is a numerical code indicating the status of the request.

      • “1” = “OK”

      • “2” = “Zero Results”

      • “200” = “Authentication failure”

      • “400” = “Violates a rule of the API”

    • RESPONSE_MESSAGE, (always returned) is a string explaining the RESPONSE_CODE.

    • RESPONSE_TIME, (always returned) server time to process the request.


    • SENSOR_VARIABLES[], summary of variables in the OBSERVATIONS element.

    • OBSERVATIONS[], contains all the observational data.

    • QC[], contains all the data attributes.

    • QC_FLAGGED, boolean value indicating data check attributes are returned (if requested).


    • QC_TESTS_APPLIED[], a list of data checks that were applied to the data.

    • TOTAL_OBSERVATIONS_FLAGGED, number of observations that have additional data check attributes.

    • PERCENT_OF_TOTAL_OBSERVATIONS_FLAGGED, floating point number indicating the percentage of the observations that have additional data check attributes.

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