Guatemalan weather conditions in 2012 displayed considerable variations from the climatological data, as was the case for the larger Central American picture. A key finding from our research is that in general the minimum daily temperatures were higher than the corresponding climatology while the maximum temperatures were lower. As a result, the daily diurnal temperature range was generally lower than the corresponding climatological range, leading to an increased number of days where the temperatures fell within the optimal range for coffee rust development during the dry season, or for the development of lesions on the coffee leaves during the wet season. The coffee rust latency period was probably shortened as a result, and farms at high altitudes were impacted due to these increases in minimum temperature. A seasonal analysis of temperature accumulation at farm locations found a direct correlation between temperature accumulation and rust severity. Overall, compared with the climatology, there was less rainfall than usual in Guatemala during the 2012 wet season. Additionally, at a number of case study farms with high rust severity, there were differences observed in the rainfall pattern during the year. There was a period of heavy rainfall between mid March and mid April, in contrast with the climatology, and before the usual start of the rainy season. During the 2012 dry season, there was a weak La Niña signal, followed by a weak El Niño signal during the wet season, which could explain the observed anomalies from the climatology. There was also a shift in the timing of the mid rainy season drought period to earlier in the season. Despite there being a general pattern of lower rainfall during the wet season when compared with the climatology, a number of the five day precipitation periods included very high rainfall events when compared with the climatology. The wet season came to an earlier end than usual in Guatemala.