Getting Started With Weather Data Services

Weather Data Services provides an easy way to access weather forecast data, historical weather observation data and historical summary data. The data is accessible in three ways – directly in the browser, as a data download or as a Restful API link.

This article steps you through the process of obtaining weather data though the Weather Data Services page.

Need help? 

For more information we have full support available to you.

Frequently Asked Questions

Also you have access to open tech support tickets if you have additional questions.

Creating an account

The initial page of the application prompts you to either log in or create an account.

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As we have never created an account before, press ‘Sign up’ to create a new account and start a free seven day trial. 

The Sign Up process will walk you through the steps to enter an email, validate the email and finally create a password.

For more information on creating an account, see How to sign up for a Weather Data & Weather API Account

Retrieving our first weather data

Once you have created an account, return to the opening log in page and sign in with your new credentials.

The first screen you will encounter will ask you to provide the locations you wish to query on. 

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There are two ways to import location into the application – either by providing a file which includes addresses or by manually entering a location.

Let’s start by entering a manual address. Press on ‘Add Manual’.

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The application asks for two pieces of information. The address of the location (which can be the full mailing address but also a partial address or latitude, longitude pair). You may also enter a name. The name is not required but if specified, it will be used when displaying weather data location instead of showing the address.

After providing your locations you will be asked for the type of query you wish to run:

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On this page you will have 3 choices of weather queries:  Forecast, Historical Data and Historical Summaries.  These options are defined as follows:

Forecast –   The forecast query type will return the weather forecast for up to 15 days from today’s date.  The actual length of the forecast may depend upon your geographical area and your subscription level.

Historical Data – The historical data query will retrieve past data as defined by the user for any time window since 1970 however the most accurate data was first collected after 1990 especially for weather variables such as precipitation and other non-temperature values.   The size of the dataset that is available will depend upon your subscription level.

Historical Summaries –  Summary data is a report of past weather grouped into days, months or years.  By providing a time window say “1989-2019” and asking for monthly data, it will bring back a summary of every month’s average weather for the locations provided.

By choosing Forecast I am immediately shown weather forecast data for the selected location:

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This is the most basic view of data. The single location weather forecast is displayed in a calendar format which each day showing multiple variables of weather data including expected high temperature, low temperature and likelihood of rain.

From this screen we can also see the raw grid of data or download data in CSV (comma separated values) format to use in Excel or import  into databases or other software.

Query Types and Options

 As described above there are three main query types:  Forecast, Historical and Historical Summaries.  In this section we will cover briefly some of the different types but refer you to other articles for more deep-dive discussions on the value or advanced uses.

Forecast

The forecast query type retrieves up to 15 days of weather forecast information depending on the location and a variety of other factors.   There are three main options that you have for this data format:  Daily, Hourly and Day/Night as seen in your interface.

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Always remember that all data is collected on an hourly basis.   When viewing data in any other time interval it is aggregated by a particular algorithm to summarize the data.

Day interval data is the aggregate of the day’s hourly values starting from 6AM (converted for that location’s local time including Daylight Savings time adjustments) until 6AM the next day.   For specific weather variables you will get the maximum of maximums, minimum of minimums and totals for any data such as rainfall or snowfall.    Please refer to our weather data documentation

this will give you a detailed view of which variables are available and how they are aggregated for larger time intervals.

The Day-night interval is very similar to the interval except each day is split into two distinct time frames:  morning and nighttime.   These correspond to 6AM-6PM and 6PM-6AM time segments and the forecast is forward looking.   In the data results for a forecast of Herndon, VA you will see the following:

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This can be read as follows:  on January 30th, 2020 the daytime forecast (starting at 6AM) has a daytime maximum temperature of 39 degrees F and a daytime low of 29 degrees F.   The nighttime forecast (starting at 6PM) will have a maximum night temperature of 37 degrees F and an overnight low temperature of 30 degrees F.  

Finally, the Hourly interval is simply an output of the hourly data as it is collected from our sources, combined and cleansed as defined here

Historical

The options for a Historical query are more advanced than with the forecast however there the time interval options are the same with the absence of the day-night interval.   For understand the time intervals please refer to the forecast section.   The first view of options for historical is as follows:

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In addition to the Interval section you will also see that a date range is requested.   This is the start and end date of the time period for which you need historical data.  Simply enter the dates and the weather for your locations between these dates will be retrieved.   The aggregations of weather variables work just as they do for the section above for Forecast query types.

To see the additional options for Historical queries click on the ‘More options’ link highlighted by the red arrow in the screenshot above.

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Business Hours

This advanced options view uncovers two additional options for a historical query:   Business Hours and Weather Station Details.

Business Hours is a feature that allows the user to isolate a specific set of hours that constitutes a working day.   PLEASE NOTE that breaking hours that crosses over a midnight barrier is not supported.   However, users can easily ask for historical data such as rainfall during store hours of 8AM-8PM to see if rainfall impacted their business.   All aggregations of data during this time works the same as standard day intervals except that the system only considers the hourly data during the Business Hours window if set by the user.

Weather Station Details

Weather Station Details is a feature that is enabled by the Visual Crossing Interpolation Engine.   In standard mode, Visual Crossing Weather is able to provide more accurate forecasts by querying multiple weather stations and geographically interpolating the results for the location you provided.    This is helpful in two main areas.  1)  rural areas that are not near weather stations will often have weather patterns that can vary and by triangulating the exact location and its proximity to multiple stations allows us to confirm and adjust weather for that specific location.  2)  Many weather stations will be missing data, this includes major cities such as Chicago where a recent weather station stopped reporting certain weather variables for an extended period.   By querying other stations, we can piece together the weather for your locations even in instances of bad or missing data.

The options for your historical query are as follows:

Include Weather Station Info –  By checking this option you can ask the system to include which weather stations were used in gathering your data.  This is helpful in understanding and confirming data.

Maximum number of Weather Stations –  This option allows the user to limit how much interpolation is utilized.  If the value is set to -1, the system will intelligently choose based on distance and data quality how many stations will be used to process the most accurate data for you.

Maximum distance to Weather Stations –  This option allows users to limit how far our system can reach to gather data.   If the value is set to the default -1 option then the system will use its internal values to determine how far it can reach just as it does with the Maximum setting.   Please note that even though distant weather stations may be chosen to contribute to the gathering of data, all stations are limited in their contribution they their geographical distance.   This means that a Weather Station that is 25 miles away will contribute much less than one that is only 5 miles away.   

For more information on how the data is gathered and interpolated please read the following blog document.

Historical Summaries

 The final query type is Historical Summaries.   The goal of the summary query is to give the user some level of reporting control without requiring downloads of large historical datasets and import actions into a tool like Excel or Business Intelligence systems.   The Historical Summaries allow users to query and group weather into larger terms such as ‘typical weather for January at my location based upon 10 years of data’.   Let’s examine the options by clicking on Historical Summaries in our query type chooser:

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We have 3 main options to work with at the basic level:  Range, Interval and Break.  Here is a brief overview of those options:

Year range –  The year range is the sample period by which the system will pull hourly data and perform its aggregation.   By default the system will choose 30 years worth of data and our recommendation is that any additional data will add no significant value for the vast amount of data it will provide.  Typically you can even reduce this down to 10 years and still show statistical significance.   Another item to consider is that any data before 1970 is probably of lower overall accuracy and quality and for variables other than temperature you may wish to go beyond 1990.

Time interval – The interval in this term is the time unit that will appear on the report.  If you want to see the report for each month, then choose month.  If you want to see sums for an entire year, then choose year.   If we choose a self-breaking report on Month it would look like the following:

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Data Breaking –  Breaks are typically a confusing topic for many, to make it simple we will try to give a few examples.   Think of breaking as a second time interval.   If you want to choose month for ALL data that you have then choose ‘Self’ breaking as we did above.   This will take data from all time (limited by our our range setting) and group them into months.   However if we want to see the data grouped by our Month interval and see it per-year, then ‘Year’ is the correct breaking choice as we see below:

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As a counterpoint to understand this if a user chose ‘Day’ as the Interval and ‘Years’ this query would show the summary for every day for every year.   This is the same as standard Historical Summary query and provides no aggregation or reporting value beyond a normal query.

The topic of Historical Summaries is a bit more advanced and can afford the user some great features.   Please refer to the following document for a more detailed usage.

Results 

Once we request weather data from a query, we will automatically be taken to the results page.  On this page the default view is the Weather Calendar.  On this page we will see a multi-location weather calendar view of our data.   This calendar view is a consumer familiar view with High/Low Temperatures, Rainfall and Wind speed.  It also includes graphical icons to display the conditions.   

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Selecting the Raw Grid option the user will get a more technical view of the grid of data which includes all of the standard weather variables. 

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At the top of this view you will see that data may be filtered by a single location in order to make the viewing faster.    This view is mostly intended as a sample of your data and not a complete viewer, however users can easily add and filter out other locations simply by using the list provided as seen below.

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Please note that if you chose in your query to see weather station data, that will also appear in this grid of data.   Many more advanced items have been left off this view such as lat/lon or wind direction data.   To see then entire dataset simply check the “Show all columns” checkbox at the top of the page. 

If you wish to export the data choose the “Download all data” button at the bottom of the grid and you will download a CSV (comma separated values) document to your browser window.   You should see a small download window at the bottom of your browser with the download status.  

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Once downloaded, this data can easily be loaded into Excel, RDBMS or any other data store.

Modifying Queries

As you can see on the results page there are 3 buttons near the top of the screen that allow for additional features.  The first two allow the user to edit locations or the query:

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Simply click on Locations and you will be shown the current list of locations and can clear, import or manually add new locations as you did previously.  The list allows for independently removing any location.

Choosing the Edit Query button will open up the same query editor as before and allows you to switch all available options on the original query.

Whether you are editing Locations or the Query, simply choose the “Retrieve weather data” button to return to the results with your latest data based upon your query/location changes.

Query API

The final action button is the Query API.  This button allows this Data Services Page to double as a Query Builder for URL and API users.   By clicking on this button you will see the following options.

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The available options in this window are as follows:

Documentation buttons – The orange buttons at the top will provide the API users with documentation links on how to build a query and utilize it in your code or application.

Base query –  The base query is an https query string that can be called from any web-enabled system such as a browser, application or data streaming mechanism.   Different forms of the query are available for GET, POST and ODATA scenarios.  Simply click on your option and you can use the “Copy full query” button at the bottom to put the URL text into your text buffer and can be pasted anywhere.

If you want to see the data results prior to pasting into another system, simply choose the “Open query in new window” button and it will paste the text into a new browser tab on your behalf.  Here you will see the raw data results in your browser as seen below.

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More Query Options –  Using the link on the API Query window the user can expose a whole host of additional query options including Unit selection, data format (CSV vs JSON) and more.

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The most important option is the API Key.   Paid users with a subscription that supports API usage will be able to use the key found here to include in their automated queries.   Usage of the key eliminates the need for session based downloads that require login.   Simply pass the key with your requests from your script or application and the system will authenticate automatically.   

Users without API privileges can always copy the Base query text and use that in a limited, expiring time frame to pull data into another application using the URL they copied.  The expiration is typically less than 10 minutes but is subject to change.   The URL that is copied will have all of the same query information embedded in the URL but will have a session token instead of an API key.

To return to the results window at any time simply click on the following button in the API Query builder page.

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Additional Sources of Information

For more information, interactive discussions please feel free to join our discussions at

The FAQ can be found at:  https://www.visualcrossing.com/resources/frequently-asked-questions-faq-for-visual-crossing-weather-data/

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