Frequently Asked Questions

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What is a Weather API?

Synoptic’s Weather API is a powerful and fully scalable service for accessing an expansive database of real-time and historical surface-based weather and hydrology observations. This RESTful API is a request-based data delivery service using a simple HTTP call that can extract minutes or years of data in seconds for locations across the globe. The Weather API allows for complete customization via an API call, allowing the user to request specific variables at any time for stations around the globe. You can also find all stations within a certain radius of a location, and more. To learn more and get access to the API, click Get Started. 

What is the National Mesonet Program?

The National Mesonet Program (NMP) is the National Weather Service’s (NWS) gold-standard public-private academic partnership data buy. By leveraging  state, local, and private sector weather observation networks, the NWS has access to tens of thousands of additional observing assets from the surface, upper-air, mobile (aircraft, balloon, and buoy), and radar, all at a fraction of the cost of deploying and maintaining these networks themselves. With 53 participating partners, , the NMP forms a true collaboration, sharing best practices and honing business models to ensure efficient and effective delivery of the highest quality observations nationwide. Synoptic continues to spearhead this program as the Lead Subcontractor.  In this role, Synoptic does all the heavy lifting for the partners from contracting to quality control to data delivery to the NWS. To learn more about the National Mesonet Program, click here. 

How can I view the available data? Is there a catalog or map to see available data sources?

You can view all publicly available weather data with our new Synoptic Data Viewer. It allows you to view real-time weather data across your area of interest, drill down to see reported conditions at specific stations, and generate custom plots of weather conditions. 

How do I access Synoptic Data’s ArcGIS real-time weather data layer?

Synoptic’s hosts a Real-Time Weather Observations feature layer on the ArcGIS Marketplace, with national, eastern, central, and western regional coverage in the United States. From there, you can click “30-Day Trial” to experiment and explore the feature layer before committing to purchasing a license. For more information about our ArcGIS offerings, reach out to You can also use the Weather API to output a geojson format that is easy to use with GIS applications.

Why is there a gap of missing data in my Time Series request / download from the Data Download tool?

There can be gaps in observational periods for a variety of reasons, including: sensor failure, hardware or software maintenance by a data provider, outages in transmissions and ingest feeds upstream of Synoptic. One way to check whether a station’s or network’s observations are reaching Synoptic in real-time is using the Availability Dashboard. If the above reference indicates there should be observations for your period of interest, reach out to for assistance.

Why did I receive the following error message: "Unauthorized. Review your account access settings in the customer console."?

This error message asks the user to review their account settings on the Customer Console’s “Customer & contract” tab. Under Access, you can view the level or type of features the account has access to. This response will typically occur if an account does not have access to the Weather API, or the Weather API service availability is not included. If you encounter this error, review our pricing page or contact for more information.

I am not seeing current observations/data for a network/station. How can I check if there's an outage?

The Availability Dashboard provides users with metrics indicating whether data is flowing through Synoptic’s system at the network- and station-levels, and how the current data flow fits in the context of the recent past. It is not meant to be a subjective assessment of network or station quality, rather whether the data is reaching Synoptic’s system. For concerns or inquiries related to the reporting status of stations or networks, please contact

What does real-time weather data mean? How fast can the data become available after being observed?

Synoptic minimizes the latency between the observation and data availability in the API, with an ingest and dissemination infrastructure capable of processing, quality controlling, and disseminating the data within seconds of arrival. For those interested in our lowest latency service, please check out Push Streaming here. 

A weather station is inactive or showing incorrect observations / data. When will the station be active again? When can you implement a fix / perform maintenance on the station?

Synoptic Data does not own or operate any weather or environmental monitoring stations or sensors. All observational data is made available by data providers with their permission to be aggregated and disseminated through our web services. In the case of a station or sensor failure, we can and will alert the data provider; however, it is out of our hands as to when or even if the station or sensor is fixed so we ask for patience  as maintenance happens at the availability of the data provider’s resources. While we can’t control the maintenance of faulty sensors, we do offer our Quality Control services that can flag and remove erroneous data.

How can I access METAR code from my local airport?

METAR code from ASOS stations can be accessed via the Weather  API.hey will be contained within the “OBSERVATIONS” key as “metar” (JSON) or under “metar” column (CSV from the Time Series Service). If using the Data Download tool, after selecting an ASOS station, under variables, select “Raw observation (text)” to receive the original METAR code.

How is the wind direction variable interpreted? What is the convention for direction variables?

Wind direction indicates the direction which wind is originating or coming from, the opposite of the direction that wind is moving towards. Wind direction is reported from true north, starting from 0° moving clockwise 360 degrees. Derived wind direction is also available as “wind_cardinal_direction” (such as N, NW, E, etc).

How do I find the source for a particular weather station or network? Where are data providers listed and referenced?

We list networks and their providers on our Documentation site, including the Synoptic network ID (MNET_ID), network long and short name, and percentage of active stations. We also offer the provider’s website inside of the Weather API output. By adding the argument “&complete=1” to an API request, the “PROVIDERS” key in the JSON output will have the URL linking to the provider’s website.

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