Imperial Weather is invaluable for scholars of both environmental history and history of science. The book joins an emerging range of works on meteorology and colonialism in the global South. Williamson maps the shift from local climatological studies by enthusiasts to official research by scientists during the period when methods and instrumentation of meteorology were being standardized. Making an original intervention in the history of tropical meteorology, she argues that colonial meteorology was more concerned with ‘trial, error and accident’ than with ‘purposeful science’ (p. 7). Imperial Weather is divided into three sections: the science of weather (Chapters 1 and 2), changing weather (Chapters 3 and 4) and controlling weather (Chapters 5, 6 and 7).

The first section focuses on how tropical weather was understood: the role of new technologies such as telegraph and radio in weather communication; the rise of new global conventions, particularly the Beaufort scale; and new practices, including mathematical modelling. The first two chapters lay the foundation for comprehending why tropical meteorology was underdeveloped as a field of study and practice in the British Empire. Williamson contrasts this with rapid advancements in the science of meteorology in the metropole and Europe at large. Meteorology’s utility in colonial Malaya lay in predicting monsoons and typhoons as well as allowing colonists to decide where to settle and how to grow crops. Williamson shows that the development of meteorology was far from a teleological process. In fact, it was mired in contestation, lack of consensus and uneven resource distribution. Malayan meteorology was not systematically organized until 1929 and was limited to ‘correlative and statistical analysis’, not garnering deep research on climate until the twentieth century (pp. 37–9). The Japanese invasion of Malaya (1942–5) led to collaboration between Chinese, Indian and Malay meteorological observers and the state, particularly prominent amongst them being Kanagasabai Narayanswamy, who manned a weather station in Perak generating weather reports. Though Malaya’s meteorology deteriorated under the Japanese, according to Williamson, the importance of the scientific practice soared during the war and led to demand for new investment.

The next section surveys changing weather. It is concerned with consciousness about man-made climate, desiccation debates and urban heat discussions. The third chapter provides insight into the desiccation debate, where Williamson contends that deforestation led to soil degradation and erosion, exacerbating the impacts of floods and droughts. Desiccationist debates had their roots in the classical period but they became mainstream in the mid- to late nineteenth century, influencing climate policy. By the early twentieth century, with the opening of the Malayan Meteorological Services in 1929, the desiccation debate had waned. In the next chapter, Williamson turns to the phenomenon of urban heating that was at the centre of the colonial state’s preoccupations about lived experience in tropical climates. Williamson argues that the measurement of global temperature remained in a fledgling state in the early nineteenth century and was largely Eurocentric. It was improved in the 1850s with the Kew Observatory’s standardization of thermometers and the Fahrenheit scale. By the early twentieth century, concerns about the role of urbanization in causing heat waves had led to recommendations about building a ‘garden city’ with many forest features preserved to cool temperatures and make the city more livable. However, with the rise of modernization in the 1960s the city became more urbanized, making thermal comfort even more important.

The last section is concerned with controlling climate, particularly inaction in the colonial government’s management of weather that amplified social stratification in colonial Malaya. Whereas enviro-technical debates were fairly advanced in the metropole, in Malaya they remained at a nascent stage. The colonial state’s sole interest in Malayan meteorology was environmental management – manipulating water, dealing with drought and removing heat and humidity – not research about tropical climatology. Williamson argues that colonial infrastructure that developed for flood water management due to rainfall extremes was rudimentary and ineffective. She goes as far as saying that ‘environmental colonialism … was a leaky vessel’ (p. 100). By the Second World War, however, the situation was much improved in colonial Malaya due to a five-year plan that addressed inundations, enhanced soil productivity and improved swamp drainage to fight rising levels of malaria. Even then the colonial state focused on risk reduction, not large-scale infrastructural improvement. The next chapter demonstrates that despite research on rainfall the government’s management of drought was limited. Internal conflicts between the Forest Department and the Land Department led to hydraulic mismanagement intensifying drought in many parts of colonial Malaya. Williamson contends that the government’s attempts at drought management were more ‘reactive than proactive’ (pp. 129–30). Singapore was a vulnerable society given its limited resources, unstable incomes and lack of institutional support. Topographically, Singapore lacked ‘high hills and steep valleys’ that were a prerequisite for constructing deep reservoirs (p. 135). This was temporarily addressed by the building of a pipeline between Malaya and Singapore that was ultimately destroyed during the Second World War. Lastly, Williamson illustrates that controlling indoor temperature through cooling technologies had a long history in colonial Malaya – originating well before American refrigeration and cooling technologies. However, these technologies were not widely available until the 1990s in Malaysia and Singapore.

Imperial Weather provides useful insights into colonial meteorology beyond the metropole. It is one of the few such studies located outside Europe and Britain. However, Williamson’s study, by her own admission, excludes indigenous knowledge that does not have a bearing on colonial science. She insists that in colonial Malaya there was no dialogue between indigenous knowledge and colonial meteorology. This claim warrants the question: was any engagement purposely undocumented or even consciously erased as was the case in India and Latin America? Some wariness towards the official colonial narrative could have proved useful for Williamson’s narrative. Still, it is a rare and persuasive study that enriches the growing field of the global history of meteorology.