changes in the future are subject to adaptive responses and socioeconomic changes, such as the shift to less climate‐sensitive activities.

While it is hard to predict what happens in the future, it is even difficult to establish the links between weather and incomes in the present. While some activities are negatively affected by wetter or warmer rainfall conditions, others may benefits from it. And Income changes do not only depend on direct weather impacts on output, but also on indirect impacts such as price or production adjustments. Decreases in crop income through yield declines could be reduced or even offset through resulting increases in prices and wages (Hertel et al., 2010; Jacoby et al., 2014). Different income activities also play various functions. Some may actually serve as a coping strategy to compensate income shortfalls from other activities so that incomes from these activities increase in times of adverse weather conditions (Noack et al., 2015). In addition, weather effects depend on socioeconomic factors that determine the extent to which households choose risker (but more profitable) activities and can manage negative impacts through production adjustments (e.g. use more irrigation).

Another difficulty results from identifying the types of weather variation that are relevant for income fluctuations. Many studies use temperature and rainfall levels defined as annual means (Burke et al., 2011; Dell et al., 2009; Feng et al., 2010; Schlenker and Lobell, 2010). Yet weather impacts depend on their timing and the seasonality of income activities, so that some studies measure seasonal weather conditions (Hsiang, 2010; Mendelsohn et al., 1994; Welch et al., 2010; Yang and Choi, 2007). Moreover, excess rain and heat waves can be as harmful as rainfall scarcity and cold spells. To capture this non‐ linearity, some studies break rainfall and temperature levels into different intervals or only measure them above or below a certain threshold (Deryugina and Hsiang, 2014; Deschênes and Greenstone, 2011; Schlenker and Lobell, 2010).<sup>3</sup> To control for abnormal values, some studies measure the deviation from the long‐term mean normalized for location‐specific variability (Baez et al., 2015; Hidalgo et al., 2010; Noack et al., 2015). Weather extremes measured by minimum and maximum temperature and rainfall levels matter too (Welch et al., 2010). Very importantly, all of these forms of weather variation can have different impacts in different places depending on location‐specific climate conditions (Park et al., 2015).

In order to define recommendations for poverty eradication in face of increasing climate risks in Vietnam, this paper attempts to disentangle the current impacts of weather variation on income changes. To better understand the income effects of different types of weather variation, the analyses differentiate between annual, seasonal, abnormal and extreme weather conditions and weather events related to rainfall and temperature. They also investigate how weather impacts vary by socioeconomic group, climate zones and income activities. By covering this breadth of impacts, this study adds to the existing literature showing that income effects depend on the type of weather variation and different contexts.

These analyses can build on two novel methodological aspects. First, this study combines data from the latest Vietnam Household Living Standard Surveys (VHLSS) 2010, 2012 and 2014 and gridded weather data

> 3 Related to this approach is the concept of degree days, which assumes a piecewise‐linear function in temperatures defines as the sum of degrees above a lower threshold and below an upper threshold intervals (Schlenker and Lobell, 2010; Schlenker and Roberts, 2009) .

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