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Atmolix Historical METAR

Historical METAR

Atmolix Historical METAR provides access to archived aviation weather observations collected through NOAA's Meteorological Assimilation Data Ingest System (MADIS). It is designed for reviewing past airport weather conditions by station, date and observation time.

How to Use Historical METAR

Use the historical search to locate an airport or weather station and retrieve available METAR observations for a specific date and time.

1. Select the station Enter the ICAO identifier of the airport or reporting station, for example LBSF, EGLL or EDDF.
2. Select the date Choose the historical calendar date you want to investigate.
3. Select the observation time Select the available observation closest to the requested time. METAR observation times are reported in UTC (Zulu) time.
4. Review the report Open the available observation to review the original METAR code and the corresponding weather information.

Historical Data Source

Historical METAR observations displayed by Atmolix are sourced from NOAA's MADIS archive. MADIS integrates aviation surface observations from multiple sources, processes them into a common format and maintains historical observation archives.

United States MADIS began collecting METAR reports over the United States on July 1, 2001.
Global coverage MADIS expanded its METAR collection to global coverage on March 13, 2006.
Archive MADIS provides archived surface observations that can be accessed by date, including historical METAR data.

Usage Limits

To ensure fair access to historical aviation weather data and maintain reliable service performance, Atmolix applies request limits to Historical METAR searches.

Per airport / user A single user may make up to 10 historical METAR requests per airport per day.
Daily service limit A maximum of 100 Historical METAR requests per day is allowed across the entire service.
Limit scope The per-airport limit applies separately to each airport for an individual user, while the daily service limit applies to all users collectively.
Limit reached When a request limit is reached, additional historical queries may be temporarily blocked until the applicable daily limit resets.

What Is a Historical METAR?

A historical METAR is a recorded aviation weather observation from a specific station at a specific observation time. Unlike a forecast, it describes the conditions that were actually reported at the station.

Station identifier Identifies the airport or weather station that issued the report.
Observation time Defines when the weather observation was made. METAR times are expressed in UTC.
Wind Provides wind direction, speed and, when applicable, gust information.
Visibility Provides reported horizontal visibility and relevant runway visual range information when available.
Present weather Reports phenomena such as rain, snow, fog, thunderstorms and other significant weather.
Cloud information Reports cloud amount and cloud-base information, including conditions relevant to aviation ceilings.
Temperature and dew point Shows the observed air temperature and dew-point temperature.
Pressure Contains the reported pressure or altimeter setting used for aviation purposes.
Remarks Additional observation details may be included in the remarks section of the report.

Working with UTC Time

Time is one of the most important details when working with historical aviation observations. METAR observation timestamps use UTC, regardless of the local time zone of the airport.

  • UTC / Z: A timestamp ending in Z is expressed in Coordinated Universal Time.
  • Local time: The local date at an airport may differ from the UTC date.
  • Midnight: Reports around 0000Z should be interpreted using the UTC date contained in the report.
  • Comparisons: Use UTC when comparing observations from different airports or different dates.

METAR and SPECI

The historical archive may contain both routine METAR reports and special observations known as SPECI. A METAR is a routine aviation weather observation, while a SPECI is issued outside the routine schedule when significant changes in weather or operating conditions require a special observation.

METAR Routine aviation weather observation issued according to the station's reporting schedule.
SPECI Special observation issued when significant changes meet the applicable reporting criteria.

Understanding Data Availability

The MADIS archive covers a very long historical period, but availability is dependent on the individual station and the data present in the archive. The beginning of the MADIS METAR collection does not mean that every airport has a continuous record starting on that date.

U.S. observations The MADIS METAR collection over the United States begins on July 1, 2001.
International observations Global METAR collection begins on March 13, 2006.
Station coverage Individual stations may have different periods of availability, reporting schedules or gaps in the historical record.
Missing observations A missing record does not necessarily indicate a lack of weather observations; the corresponding observation may simply not be available in the archive.

Typical Uses

Flight analysis Review historical wind, visibility, cloud and pressure conditions around a flight or airport operation.
Weather verification Determine what conditions were actually reported at an airport at a particular time.
Historical research Investigate past weather events, changing conditions and aviation weather patterns.
Airport comparison Compare observations from multiple stations using the same UTC time reference.

Example Workflow

To investigate historical weather at Sofia Airport, enter the airport's ICAO identifier LBSF, select the required historical date, choose an available observation time and open the corresponding report. The report can then be examined using both the original METAR notation and the available decoded weather parameters.

Usage Limits

To ensure fair access to historical METAR data and maintain stable service availability, Atmolix applies daily request limits per user.

10 requests per airport Each user can make a maximum of 10 Historical METAR requests per airport per day.
100 requests per day per user Each user can make a maximum of 100 Historical METAR requests in total per day, regardless of how many different airports are queried.
Combined limit The 10-request airport limit applies individually to each airport, while the 100-request limit applies to the user's total Historical METAR requests across all airports.
Daily reset The request counters reset daily.