Weather File Feed -Technical Details

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Weather File Feed in Detail

Foreca Weather Feed, providing all the same weather parameters as  Foreca Weather API, is available as XML and delimited ASCII

Service

Foreca provides raw weather data in an easy to use format for customers who want to design their own graphics, or who just need raw weather data for other purposes. Readymade Global or National packages are available - both with two different levels of service: Standard and Premium. For special purposes custom feeds are also available upon request. Depending on the package chosen the feeds contain weather forecasts for up to 14 days, and current conditions data from relevant local weather stations.

The data is updated on a continual basis. With a Foreca Weather Feed your weather data will always be up to date.

Pricing is based on the package chosen and the end usage of the data. Any customer requested tailoring is charged separately. Graphical symbol sets are available for visualizing the weather data.

A Foreca Weather Feed can contain weather information for up to 80.000 locations world-wide. Please note that the actual number of locations and pricing is subject to negotiations.

Technical Requirements

The Weather Feed is based on customer using HTTP polling to monitor forecast and observation files, which update at different intervals. Location meta data, such as coordinates and names in various languages, is provided in a separate static file. The files are either XML or delimited ASCII raw data, which is language independent. We recommend that larger batch files be gzipped delimited ASCII, since typically the delimited ASCII files are faster and easier to parse and gzip compression greatly reduces transfer times. For convenience (intended for smaller files) we can also provide the data as uncompressed XML, or RSS. Foreca reserves the option to limit traffic to only predefined IP adresses.

Polling

The exact update time may vary slightly from day to day, and there can be extra updates. To optimize data freshness and to create a robust system, please adhere to the following polling method:

  • For each XML data file, get the HEAD every 10 minutes. If the file on our server is fresher than your local copy, then download entire file.
  • For each image XML meta file (which describes the images in an animation), get the HEAD every 10 minutes. If the file on our server is fresher than local copy, then download entire file, and all the images referenced by the meta file.
  • For warning files, get the HEAD every minute. If the file on our server is fresher than local copy, then download entire file

The HEAD of a file is typically only hundreds of bytes and creates negligible traffic. For reference regarding the HEAD request, see http://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html section 9.4, HEAD. Foreca does not endorse any particular tools, but simply running wget in mirroring mode accomplishes the above.

Product Packaging

The examples of country locations sets can be found here.

Global and National packages can be combined. For instance, Standard Global package with 20.000 location including 352 UK locations UK Standard package with 2300 UK locations (all the locations included in the Global package and over 1800 additional locations). This combination provides complete coverage of the UK and all major locations globally.

Weather data provided

Weather parameters can be found here.

The service is delivered in up to four separate files, which are detailed below.

Foreca provides graphical icons for visualizing the weather codes, which are (C) Foreca but can be freely used to visualize Foreca's weather data.

Daily overview forecasts

This file contains summary-level weather parameters which are applicable for the entire day, such as the day's maximum temperature. Forecasts are updated at least four times per day.

Hourly and 6-hourly forecasts

This file contains snapshot-like weather parameters for the times specified, such as temperature, wind speed, etc. This data could for instance be used to plot a graph of a weather parameter as a function of time. Forecasts are updated at least four times per day.

Current conditions

For each location, this file contains data from the closest relevant weather station at the time, if available. The file is updated at least every 15 minutes, but the update frequency of any given observation station's data depends on the transmitting frequency of the station, which typically varies between 30 minutes and 3 hours, but there are also some manual stations which do not take measurements during the night. When we choose which stations to use we try to ensure that the weather conditions are as close as possible to the ones at the location they are used to represent. To do this, we weigh the following factors:

  • distance to the station
  • altitude difference between station and forecast location
  • how recent the data is
  • estimated time of next update based on historical update frequency
  • how rich data the station provides (e.g. some stations do not provide cloudiness, which is needed for graphics)

Due the above factors, a more close-by or recent observation might not be used, if it only contains temperature. We might opt for a slightly older observation from another station, if it contains more weather parameters. This process is dynamic, so it is possible for the weather station chosen for a given location to change, as new data becomes available. One example situation where a station can change frequently happens when a close-by station transmits rich data during day time but ceases transmitting during the night, which is typical for smaller air ports. In such a case a different station would be selected for night time.

Please note that in some parts of the world the observation network is really sparse, such as in Africa, parts of Middle East, and South America, and especially during night time.  The closest weather station with fresh data can at times be over 500 km away. In such cases it is possible that the current conditions will be completely missing from the feed.

While the forecast data will always be there, please be prepared to handle missing current conditions (observations) information, since missing instrumentation or instrument malfunctions may affect data. Any of the parameter values can be missing/empty, and even the entire obs tag (in XML) can be missing. In delimited ASCII empty data is denoted by an empty string between the delimiters. In case of missing data it is recommended to simply adapt lay-out so that white space is shown instead. Texts like "No data" are NOT RECOMMENDED, as they are often interpreted by end-users as a service malfunction, which is not the case.

Weather Parameters Available

Depending on the package chosen (Standard, Premium), the feed contains current conditions data from relevant local weather stations and weather forecasts for up to 14 days. For special purposes, customised feeds are also available upon request.
 Current Conditions
 

Current weather conditions are shown for the named locations based on the nearest weather stations. Foreca gathers the observation data only from the official SYNOP and METAR weather stations to ensure high-quality data. The file is updated at least every 15 minutes, but the update frequency of any given observation station's data depends on the transmitting frequency of the station, which typically varies between 10 minutes and 3 hours; there are also some manual stations that do not measure during the night. When we choose which stations to use, we try to ensure that the weather conditions are as close as possible to the ones at the location they represent. Optionally, the feed provides also the observations from the past day for selected stations and parameters.

Weather Parameters Standard Premium
Observation time Included Included
Weather station name Included Included
Temperature  Included Included
Foreca symbol code  Included Included
Distance to station Included Included
"Feels-like" temperature Included Included
Wind speed Included Included
Wind direction Included Included
Relative humidity Included Included
Air pressure Included Included
Visibility Included Included
Pressure tendency   Optional
Station type (SYNOP, METAR), station ID (EFHK, 2097)   Optional
Extended present weather code   Optional
Precipitation amount   Optional
Dew point   Optional
Cloud cover   Optional
 Daily Overview Forecast
 

Daily forecast is a 24-hour summary of the day. The data is provided for the next 14 days, including the current day. Forecasts are updated at least four times per day.

Weather Parameters Standard Premium
Weather code and symbol 5 days 14 days
Daily forecasted high and low temperatures 5 days 14 days
Precipitation amount (rain or snow) 5 days 14 days
Wind speed maximum 5 days 14 days
Wind direction (at the time of maximum speed) 5 days 14 days
Probability of precipitation   14 days
Probability of thunder   14 days
Sunrise time, sunset time (local time or UTC)   14 days
Day length in minutes   14 days
Cloudiness   14 days
Moon phase   Optional
Moon rise/set time (local time or UTC)   Optional
UV index (today + three days)   Optional
Geomagnetic index   Optional
Air pressure   Optional
Sea water temperature   Optional
Last-updated time   Optional
30-Day Forecast

The following parameters are optionally provided for the next 30 days.

Weather Parameters Standard Premium
Day min temperature range (min-min, min-max)   Optional
Day max temperature range (min-min, min-max)   Optional
Precipitation probability   Optional
Weather icon   Optional
Sun rise/set/daylen   Optional
Day min/max temperature   Optional. 

Hourly Forecast

With hourly forecast data you are able to provide weather forecasts in one-hour-steps. Hourly forecast is adequate to show detailed weather forecast of the current day as a table or graphical module. Forecasts are updated at least four times per day.

Weather Parameters Standard Premium
Weather code and symbol   24 hour
Temperature   24 hour
"Feels-like" temperature   24 hour
Precipitation amount   24 hour
Wind speed   24 hour
Wind direction   24 hour
Relative humidity   24 hour
Air pressure   24 hour
Probability of precipitation   24 hour
Probability of thunder   24 hour
Cloudiness   24 hour
UV index (today + three days)   Optional
Solar radiation   Optional
Dew point   Optional
Last-updated time   Optional
 
 5-Day Forecast
 

For the next five days, the feed contains all the most consumed weather parameters in 3- or 6-hour time steps depending on the chosen service level.

Weather Parameters Standard Premium
Weather code and symbol 6-hourly 3-hourly
Temperature 6-hourly 3-hourly
"Feels-like" temperature 6-hourly 3-hourly
Precipitation amount 6-hourly 3-hourly
Wind speed 6-hourly 3-hourly
Wind direction 6-hourly 3-hourly
Relative humidity 6-hourly 3-hourly
Air pressure 6-hourly 3-hourly
Probability of precipitation   3-hourly
Probability of thunder   3-hourly
Cloudiness   3-hourly
UV index (today + three days)   Optional
Solar radiation   Optional
Dew point   Optional
Last-updated time   Optional
More Information
More Information Standard Premium
Amount of locations world-wide 20.000 80.000
Weather data determined to be linked to foreca.com No No
Foreca's logo must be shown next to the weather data Yes Yes
Complimentary images for weather code visualization (gif, png) Yes Yes
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Locations

Foreca Weather Feed provides forecasts for up to 80.000 named locations. The needed locations can be chosen in your feed from among global and country packages. The global package contains 20.000 locations from all over the world. For dense local locations, the country packages offer more locations within the countries. The number of locations depends on the country. Some examples of the amounts are listed below

Some examples of country location sets:

  • Russia 3.900
  • Finland 400
  • Sweden 300
  • Germany 4.600
  • France 5.700
  • United Kingdom 2.300
  • United States 9.800
  • Spain 2.900
  • Italy 5.000

Global and Country packages can be combined. For example: Standard Global package with 20,000 location including 352 UK locations and UK Standard package with 2,300 UK locations (all the locations included in the Global package and over 1,800 additional locations). This combination provides complete coverage of the UK and all major locations globally.

Delivery

Our services are reasonably priced based on the customer use case, the service usage volume and amount of customisation work required. We would be happy to offer you our pricing quote after we have specified together your requirements for the service. Our value proposition is to always deliver a weather service that is a perfect fit for the customer need. To be able to focus on major customer projects currently we are not offering freemium services or short term project deliveries.

The Weather Feed is based on customers using HTTP polling to monitor forecast and observation files, which update at different intervals. Location metadata, such as coordinates and names in various languages, is provided in a separate static file. The files are either XML or delimited ASCII raw data, which is language-independent. We recommend that larger batch files be gzipped delimited ASCII, since typically, delimited ASCII files are faster and easier to parse, and gzip compression greatly reduces transfer times. For convenience (intended for smaller files), we can also provide the data as uncompressed XML or RSS. Foreca reserves the option to limit traffic to only predefined IP addresses.

For further questions