The tyranny of distance has always figured significantly in accounts of New Zealand’s place in the world. In these accounts the emergence of new technologies: steam ships, telegraph cables, refrigeration, satellite connections, and aircraft have all transformed New Zealand’s geographies of connection. Aviation in particular has been celebrated the technology par excellence in drawing New Zealand closer to the rest of the world. Yet these celebratory tales of technological success gloss over the practical work of technoscientific assemblage that has made possible new, and enduring forms of connection. This paper focuses on the assemblage of aviation routes across the Tasman Sea between New Zealand and Australia in the late 1930s. Central to the making of this airspace was the concomitant development of specific meteorological networks that would transform the Tasman into a forecastable weatherspace. The paper identifies the layers of sociotechnical practice involved in assembling an oceanic weatherspace between national jurisdictions and observational networks. Within this new assemblage the paper focuses on the developing relationship between meteorologists and pilots, and argues that emerging tensions between these actors centred on the negotiation of the novel relationships of expertise and authority that had developed within the forecasting assemblage supporting trans-Tasman aviation.