The paper estimates the countervailing climatic factors driving the timing of US corn planting decisions. We combine very diverse sources of data, including daily fine-scale satellite-derived information, to infer the timing of planting decisions over the past 30 years at the county-level. We match this information with daily data on temperature and soil moisture conditions to assess their contributions to the planting decision. Using a panel logit model we find that warmer spring temperatures increase the probability of planting, while extremely low or high levels of moisture reduce it. We find that the levels of moisture necessary to fully offset the season-expanding effect of a temperature rise of 3ºC would need to be very extreme, suggesting that the growing season for corn is likely to expand with climate change.