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With the growing relevance of urbanized environments in the framework of adaptation and mitigation plans, improvements in monitoring the urban weather, and specially in the knowledge of the urban climatology and its evolution, are urgently needed. A basic difficulty arises from the fact that dedicated surface observational networks with the desired characteristics of measurement quality and continuity are often lacking in cities, while remote sensing data are mainly used for specific aspects, as for instance the Surface Urban Heat Island, while air temperature is more important for applications. After the experience gained, and the methodologies developed in Milan during a locally co-funded project (ClimaMi: https://www.progettoclimami.it/), the possibility was investigated of a medium- to high-resolution urban climatology mainly derived from observed air temperature and precipitation data.The urban specialized surface network (by Fondazione Osservatorio Meteorologico Milano Duomo: FOMD), in operation since 2011 and “metrologically” tested during MeteoMet Project (Merlone et al., 2015), was considered as a reliable basis for a new and more detailed analysis of the most recent urban climate in Milan. To complement the necessarily limited number of high quality measurements by this urban Climate Network (CN), other automatic weather stations (as homogenous as possible to CN) were accurately selected from third-party networks, in particular from the regional (ARPA Lombardy) meso-synoptic one, and from a private citizens association (MeteoNetwork): this helped in setting up a database of reliable hourly observational data (and metadata) in urban and peri-urban environments, dense enough for a mesoscale description of the city main statistical characteristics and for an already significative time span of 5 years.Nevertheless, resilience plans by local authorities and professionals often require a spatial resolution of the order of tens of meters: to significantly improve the spatial resolution, space-borne sensors are an obvious and nowadays practical possibility. Furthermore, to make the best use of the quality of (under sampled) surface measurements, and of the high spatial resolution offered by remote sensed data, a cokriging-based methodology (Goovaerts, 1999) was developed and tested for air temperature. While direct correlation methods between Land Surface Temperature (LST) and the (more interesting and required) near-surface air temperature are not straightforward and generally unreliable, the encouraging results obtained in reconstructing air temperature fields by cokriging allowed an analysis of the recent climate of the cities and neighborhoods at medium to high spatial resolution for selected weather types of particular relevance in the definition of resilience measures.The same methodology is now under test for precipitation measurements by different sensors and networks, and first results will be presented together with the unprecedented climatological description of temperature in the greater Milan, and analysis of micro-scale urban climate variations in consideration of (present and future) climate monitoring and assessment needs.

Resilience plans to cope with climate change are of particular relevance in cities, because of the large and still increasing percentage of population living in urbanized environments. Urban adaptation implies general planning, but reflects also in single and limited urbanistic, engineering and architectural projects, in which local authorities as well as professionals and practitioners are directly involved.The basic concept of ClimaMi (www.progettoclimami.it), a locally funded but easily replicable project for the city of Milan and immediate neighborhood (a densely populated and industrial area in the western-central part of Po valley in northern Italy), relies on the need to provide, bottom-up, updated and useful climatological information to agencies and personnel directly involved in public and private enterprises and management practices, which have immediate impact in present and future urban climate and citizens wellness. The 3 years Project was therefore developed as an interdisciplinary activity, directly involving not only climatologists but also local professional organizations, and producing as a first result a common basis of knowledge and technical language among different disciplines.A second fundamental task has been the creation of an as much as possible complete database of 7 essential climatic variables and relevant derived indexes (94 in total) for specific applications, representing an updated and detailed description of the urban environment in the most recent climate. Relating mainly on a high-quality and metrologically managed climate network of urban automatic weather stations (CN by OMD), and integrating data from stations of third-party networks according to accurate selection criteria for homogeneity and reliability, a 6 years DB for 19 selected points and 6 different time windows is now openly available to professionals for direct and immediate use in their activities.A further development has been the production of interactive GIS-based maps of air temperature distribution at medium-high resolution (100 m) in the Project area: a climatological and geostatistical methodology has been in this case applied to optimally integrate near surface measurements and space-borne observations of land skin temperature. The result is an Atlas of mean thermal fields in selected typical weather situations of specific relevance for resilience applications, for instance in case of enhanced Urban Heat Island and Heat Wave episodes. In the third and last Project year (2021), a DB and Atlas update is planned, while similar methodologies are specifically applied to precipitation.In order to make the Project results as effective as possible with real impacts on planning and project activities, numerous capacity building courses have also been planned and activated, involving hundreds of officials and professionals. Furthermore, practical laboratories and case studies were performed in order to evaluate the real effects in the aware and informed use of updated climatological information in adaptation projects.