During the 1980s, some national weather services began commercializing part of the meteorological data they collected with surface stations, radar networks and balloons. Accordingly, they ceased to supply part of the data to the World Meteorological Organization (WMO), the United Nations body in charge of weather affairs and mandated to redistribute the data among all its State Members. These policies created tensions with those weather services committed to the free and unrestricted data exchange -some of them responded in kind and stopped providing their data too. This escalation of data retaliation, known by the actors as the “Data Wars”, threatened the international system of data sharing encouraged by WMO since its creation in 1950, based on making weather data collected with national resources accessible to all. By the early 1990s, WMOs officers and professional meteorologists feared that the data sharing system would collapse. This crisis was eventually averted by the “Resolution-40” adopted unanimously during the 1995 WMO Congress, which aimed to regulate what data should be shared unrestrictedly with all and what for which commercial fees could be applied. Some years later, along the 2010s, the increasing presence of private companies providing weather data on a commercial basis on the one hand, and the shift of data management from governmental-funded programs to Big Tech corporations through their cloud infrastructures on the other hand, challenged the truce marked by “Resolution-40” and destabilized, once again, the international system of weather data sharing.

In this talk, I will look at these turbulent episodes to illustrate various institutional, technological, political and financial efforts and frictions involved in maintaining an international system of data sharing in meteorology, and the power relations that go with them. Ultimately, I will argue that, despite common discourses and imaginaries of collaboration in meteorology practice, be it for war, finances, trade or other interests, what data is shared, with whom, and under what conditions is something that must be explained historically.