expenditures.<sup>12</sup> Separate surveys were administered to the leaders of each locality on services and programs available at the locality.

For the health outcome analyses we use the _Encuesta Nacional de Nutricíon_ (National Nutrition Survey) collected by the _Instituto Nacional de Estadística y Geografía_ (INEGI) (National Institute of Statistics and Geography) and the _Secretaría de Salud of Mexico_ (Secretary of Health) in the last quarter of 1999.<sup>13</sup> The survey interviewed 7,180 rural households in 767 different localities. The survey collected general information on all members of the household and more detailed information, including anthropometric measures and illnesses in the past 2 weeks, for females between 12 and 49 years of age, and for all children 12 years or younger.

The climate data used in this paper come from the Mexican Water Technology Institute ( _Instituto Mexicano de Tecnología del Agua_ —IMTA). The IMTA has compiled daily weather data from more than 5,000 meteorological stations scattered throughout the country. The data span a very large period of time—from as far back as the 1920s to 2007—and contain information on precipitation, and maximum and minimum temperature.

The meteorological stations registered these variables on a daily basis and we used this information to interpolate daily values of these variables for a geographic centroid in each of the country‘s municipalities<sup>14</sup> . The centroid was determined as the simple average of the latitude and longitude coordinates of all the localities listed in INEGI‘s 2005 catalogue corresponding to each municipality, which resulted in a locality-based centroid. We chose this method over a population-weighted average because that alternative would bias the interpolation towards urban rather than rural areas. The interpolation method used is taken from Shepard (1968), a commonly used method which takes into account relative distance and direction between the meteorological stations and the centroids (see Appendix 5).

We carried out an independent interpolation for every day between 1950 and 2007, for each municipality. Since not all meteorological stations existed throughout the entire period and

> 12 MxFLS collects information on the value spent purchasing various categories of goods—food, dining out, healthcare, transportation, personal items, education, recreation, cleaning services, communications, toys/baby articles/childcare, kitchen items and bedding, clothing, tobacco, gambling, appliances and furniture, and other expenses—as well as the value of goods consumed from own production or received as gifts.  Unfortunately the value of goods consumed from own production versus the value of goods received from others cannot be separated. 13 Although the MxFLS also collected anthropometric measures for the household members, we choose not to use them as we can only get accurate height-for-age information for the first wave observations and of the potential under 36 month olds we lose about 30% due to non-measurement  and an additional 20% due to other missing information.

> 14 We took INEGI‘s 2005 catalogue of localities, which contained 2451 municipalities.

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