When the cold arrives: Aemet anticipates a beginning of November with differences between the north and the south

AEMET issues its official warnings through the National Plan for Prediction and Surveillance of Adverse Meteorological Phenomena, known as Meteoalert. The process consists of observing the atmosphere, making a forecast, assessing the danger by zones, issuing the warning, and continuously reviewing it. There is a fundamental distinction: AEMET warns of meteorological danger; Civil Protection decides on emergency measures and alerts to the population.

1. Meteorological observation and surveillance

The agency gathers data from meteorological stations, radars, satellites, and atmospheric soundings. This information allows knowing what is happening and feeding the numerical models that calculate the weather evolution. The prediction and surveillance teams contrast these observations with forecasts and their knowledge of each phenomenon's behavior.

2. Evaluation of the forecast and thresholds

Specialists analyze the expected intensity, the probability of the phenomenon occurring, its duration, and territorial extent. Then they apply the criteria and thresholds of the Meteoalert Plan, defined for phenomena such as rain, storms, snow, wind, extreme temperatures, or coastal storms.

Thresholds are not the same throughout Spain: they depend on the phenomenon, the area, and the considered time interval. Therefore, the same amount of rain can generate different levels in two territories. It also matters whether that precipitation is concentrated in one hour or spread over several.

3. Assignment of the level and delimitation of the warning

With that evaluation, AEMET determines the danger level and specifies the affected territory and period. There are three warning levels:

• Yellow: low danger for the general population, although certain activities, people, or vulnerable assets may suffer impacts.
• Orange: significant danger, with the possibility of serious impacts, especially in exposed areas or among vulnerable people.
• Red: extraordinary danger, with the possibility of very serious or catastrophic impacts.

Green indicates the absence of warnings for phenomena reaching the established thresholds; it does not constitute a fourth warning level.

4. Preparation, publication, and transmission

The warning identifies the phenomenon, level, affected area, start and end times, estimated probability, and relevant forecast values. It is published on AEMET's official channels and transmitted to the agencies responsible for emergency management. It is also disseminated via CAP, an international format that facilitates its exchange between systems.

According to the official warning help, the ordinary time slots are: from 07:30 to 09:00 for the current day; from 10:30 to 11:30 for the next two days; from 17:00 to 19:00 for a general review; and at 23:50 for the third day's advance. These are indicative times, not a limitation for issuing urgent warnings.

5. Continuous monitoring and updating

Surveillance continues after publishing the warning. If observations or forecasts change, AEMET can raise or lower the level, modify zones and times, extend its validity, or cancel it. It can do so at any time: the warning is updatable information, not a closed forecast.

6. Coordination with Civil Protection

Civil Protection combines meteorological information with observed impacts, territorial vulnerability, and operational situation. It is responsible for deciding the activation of plans, restrictions, evacuations, or sending ES-Alert messages. As Demócrata explains about both systems, a red warning does not automatically activate a mobile alert: these are different decisions, although related.

The State Meteorological Agency (AEMET) exercises the State's meteorological authority and provides state public meteorology and climatology services. Its competencies cover forecasting, warnings for hazardous phenomena, atmospheric observation, climate services, and support for navigation, defense, and other public policies. Its main regulatory reference is the Statute approved by Royal Decree 299/2026, of April 8, published in the BOE on April 9.

Legal competencies

Articles 1, 3, and especially 8 of the AEMET Statute define its functions:

• Information and warnings: to prepare, supply, and disseminate meteorological information and forecasts of general interest throughout the national territory, and issue warnings about phenomena that may affect people and property.
• Aerial and maritime navigation: to provide the meteorological services necessary for the safety, regularity, and efficiency of air traffic and the safety of maritime traffic.
• Defense and security: to supply meteorological information and support to the Armed Forces and the State Security Forces and Corps.
• Climate and environment: to scientifically advise administrations on variability and climate change, prepare and update climate change scenarios, and provide climate services.
• Observation and infrastructures: to continuously monitor meteorological, climatic conditions, and atmospheric composition; establish, manage, and maintain observation networks, systems, and technical infrastructures.
• Data: to preserve and update historical meteorological and climatological data and manage an open compilation of national climate information, fed by various public networks.
• Research and specialized services: to develop studies, innovation, and scientific projects; offer advice, consultancy, and technical assistance to public entities, companies, and individuals.
• Cooperation and training: to participate in international organizations and projects, exchange data, contribute to development cooperation, and carry out training, documentation, and communication activities. It also supervises its construction projects.

Regulations governing its actions

• Constitution, article 149.1.20: constitutes the state competence basis in meteorological service matters, expressly mentioned in the preamble of the 2008 Statute.
• Royal Decree 299/2026: contains the new Statute, updates the organization, and specifies competencies, powers, territorial collaboration, planning, and controls. AEMET is attached to the Ministry for the Ecological Transition and the Demographic Challenge through the State Secretariat for the Environment.
• Law 40/2015, on the Legal Regime of the Public Sector: regulates its nature as a state agency, legal personality, autonomy, and operation. Article 2 of the Statute specifically refers to its title II, chapter III, section four.
• Aeronautical regulations: article 3 of the Statute refers to Regulation (EU) 2024/2803 on the Single European Sky, Law 21/2003 on Air Safety, and Annex 3 of the Chicago Convention.
• Financing and transparency: manages the meteorological fee of article 36 of Law 13/1996. The Public Prices Resolution, of December 30, 2015, regulates meteorological and climatological services. Its transparency is also subject to Law 19/2013.

Limits and distribution of responsibilities

AEMET provides information and support to civil protection institutions: issuing meteorological warnings does not equate to managing emergencies. It can collaborate with autonomous communities and local entities, respecting their competencies. Also, although it is the exclusive provider of meteorological support to air navigation in the space under Spanish responsibility, national supervision and aeronautical meteorological authority correspond to the Ministry. The Statute recognizes administrative powers for its purposes but expressly excludes expropriation powers.

In Spain, a weather forecast for a municipality does not acquire official status simply because it is published by the town hall. What matters is who issues it, what competencies they have, and for what it is used. The consulted regulations do not include a general homologation procedure that allows any municipal forecast to become an official meteorological prediction.

1. Origin from a competent body

The state reference is AEMET. Article 8.a of its Statute, approved by Royal Decree 299/2026, assigns it "the preparation, supply, and dissemination of meteorological information and forecasts of general interest for citizens throughout the national scope," as well as warnings and forecasts about phenomena that may affect people and property.

There are also autonomous services with their own competencies. For example, the Catalan Meteorology Law assigns the Meteorological Service of Catalonia functions of forecasting and monitoring, as well as official meteorological advice to administrations competent in civil protection. Therefore, official does not mean exclusively issued by AEMET: the competence scope of each body must be considered.

2. Differentiating municipal preparation and dissemination

A town hall can disseminate a forecast from AEMET or the competent autonomous service. In that case, the official origin corresponds to the meteorological body, while the municipality acts as a disseminator.

However, contracting a company, installing a meteorological station, or preparing its own forecast does not by itself prove that same condition. Nor is it enough to use AEMET data: a new preparation based on its data should not be confused with a forecast issued by the Agency.

Article 4 of the AEMET Statute allows agreements with local entities. It is a collaboration channel, not a universal requirement to reproduce any forecast nor an automatic homologation of municipal forecasts.

3. Information that should accompany it

For communication to be verifiable and useful, it should include the following elements. These are good practices of identification and quality, not a general list of legal requirements that, when met, grant official status:

• Issuer and source: identify who prepared the forecast and provide access to the original.
• Date and validity: indicate when it was issued or updated and what period it covers.
• Geographical scope: specify whether it refers to the urban center, an area, or the entire municipal term.
• Content and uncertainty: indicate the forecast variables and, when appropriate, probabilities, intensity, and limitations.
• Integrity: distinguish the original content from any municipal interpretation, summary, or recommendation.

The municipal forecast help from AEMET is relevant: conditions can vary within the same municipality due to its extension and altitude differences. Geographic precision should not be assumed.

4. Additional rules for emergencies

It is necessary to separate forecast, meteorological warning, and activation of an emergency plan. A forecast describes the expected weather; a warning communicates a meteorological danger; plan activation corresponds to the competent authority according to the applicable procedure.

For civil protection, attention must be paid to the Directive on adverse meteorological phenomena and the corresponding autonomous or municipal plan. Incorporating information into a plan does not automatically make its author a meteorological authority.

In short, the essential check is competence of the issuer, faithful identification of the source, and correct use of the product. Institutional publication and technical quality are important but do not replace that competence.