2024 was the hottest year on record for the Italian capital, with rising trends across all temperature-related indicators and their impacts on people. This was compounded by a decrease in annual rainfall and an increase in episodes of intense and violent precipitation. And the future is not looking much brighter as summer heatwaves are projected to rise by up to 186%. CMCC presents a comprehensive climate analysis for Rome: an interactive monitoring system with ultra-high-resolution climate indicators to support the identification of locally tailored climate adaptation actions.

Rome must prepare for the heat. Analysis of past climate indicators and future projections leaves no doubt. The intensification of heatwaves, the rise in average temperatures, and the increase in extremely hot days have been the new normal for Rome in recent years, with trends revealing both an acceleration and intensification of these phenomena in the decades to come.

The first Climate Monitoring Report for Rome – the result of an innovative scientific and technical collaboration between CMCC and the Metropolitan City of Rome Capital – provides essential information to understand current and future trends in climate indicators. The report is a first example of how advanced scientific research, powered by ultra-high-resolution tools, can inform decision-making on climate issues and trigger change. This new monitoring service was created to deliver data and operational tools to tackle the effects of climate change both concretely and on a localized scale.

The report is the outcome of a multi-year collaboration between CMCC and Rome’s municipal administration. CMCC has supported both the scientific groundwork for developing Rome’s Climate Adaptation Strategy and the public consultation process.

Key data highlights

Record-breaking data for 2024: the hottest year since 1991
CMCC’s report shows that 2024 was Rome’s hottest year on record since 1991, with an average temperature of 19.7°C, 2.5°C higher than the 1991–2020 average. The data highlights a critical situation across all indicators:

• 36 tropical nights with minimum temperature above 25°C, nearly 30 more than the 1991–2020 average
• 5.4 additional summer heatwaves compared to the reference period
• 53 days with extreme thermal discomfort (perceived temperature above 45°C), 29 more than the 1991–2020 average

2024 was also characterized by below-average total precipitation, although it also experienced episodes of extreme rainfall. November was especially anomalous, with almost no precipitation recorded by local weather stations.

This is not an isolated case: 2024 follows a critical sequence of hot and dry years including 2022 and 2023, all characterized by high average temperatures and increases in the occurrence of alarming heat-related indicators such as tropical nights, scorching days, and heatwaves.

Projections to 2050: Critical scenarios across all indicators

Climate projections for 2050 show a further worsening of the situation under all analyzed IPCC scenarios. In the intermediate RCP4.5 scenario (“strong mitigation”), the data shows:

• +1.5°C increase in average temperature compared to 1981–2010
• +22 tropical nights (minimum temperature above 20°C)
• +186% increase in summer heatwaves
• +12 days with extreme heat stress due to combined humidity and high temperatures

In the most severe scenario, characterized by high greenhouse gas emissions (RCP8.5), the average temperature could rise by 1.9°C, with 28 additional tropical nights and a +243% increase in summer heatwaves.

The Dataclime platform: Precision monitoring at the neighborhood level

The monitoring service was made possible using Dataclime, a platform developed by CMCC that integrates multiple data sources – weather stations, CMCC climate models, and satellite data – to provide a robust and reliable reading of the urban landscape.

This interactive monitoring of key climate indicators allows for the identification of the most vulnerable areas, such as urban heat islands at a local scale. The service aims to assist all stakeholders – researchers, consultants, engineers, architects, planners, businesses, and public authorities – involved in urban and neighborhood-level adaptation strategies.

The collaboration between CMCC and Rome represents an innovative science-policy interface model that could significantly influence future collaboration with local administrations. The approach demonstrates how scientific knowledge can be incorporated into political decision-making, turning environmental policy into a catalyst for change.

The co-production approach to climate services – with researchers and policymakers working together – can inspire similar efforts in other urban areas and demonstrates the ways in which local authorities can become key actors in climate adaptation. The data presented provides a solid scientific foundation to guide climate adaptation policies in Rome, whilst also offering a replicable model for other European cities.

Operational support to the adaptation strategy

The service provides operational support for the implementation of Rome’s Climate Adaptation Strategy, approved on January 14, 2025. The strategy identifies four main priorities: intense rainfall and flooding, water supply security, adaptation to rising temperatures, and impacts on coastal zones.

The initiative is part of the methodological framework of the RAST – Regional Adaptation Support Tool, promoted by the EU Mission on Climate Adaptation. Rome is among the 100 European cities selected by the European Commission to achieve climate neutrality by 2030, making it a pilot case for Europe.

Advanced scientific methodology

The report is based on CMCC’s ultra-high-resolution dataset (VHR-REA_IT), which uses climate reanalyses to reconstruct past climate conditions and provide accurate comparisons with present-day data. The integration of multiple sources offers a solid and reliable interpretation of the urban environment to guide future climate adaptation measures.

The first climate monitoring report for the Metropolitan City of Rome was presented during the “Reducing the impact of heat in Rome’s neighborhoods” event, held at Sala della Protomoteca in Piazza del Campidoglio, Rome. The report is one of the outcomes of the European project Adaptation AGORA, coordinated by CMCC.