in this study we used meteorological parameters and predictive modelling interpreted by model explanation to develop stress metrics that indicate the presence of drought and heat stress at the specific environment. We started from the extreme temperature and precipitation indices, modified some of them and introduced additional drought indices relevant to the analysis. Based on maize's sensitivity to stress, the growing season was divided into four stages. the features were calculated throughout the growing season and split in two groups, one for the drought and the other for heat stress. Generated meteorological features were combined with soil features and fed to random forest regression model for the yield prediction. Model explanation gave us the contribution of features to yield decrease, from which we estimated total amount of stress at the environments, which represents new environmental index. Using this index we ranked the environments according to the level of stress. More than 2400 hybrids were tested across the environments where they were grown and based on the yield stability they were marked as either tolerant or susceptible to heat, drought or combined heat and drought stress. presented methodology and results were produced within the Syngenta Crop Challenge 2019. Maize (Zea mays L.) is one of the world's most important crops. Every year, breeders create a large number of experimental hybrids and measure their performance across different environments to select hybrids with the highest yield. The best hybrids have been identified by trial and error. However, this process can take many years 1. Research question of Syngenta Crop Challenge in Analytics 2019 was the following: Can environmental data be aggregated into useful metrics representing stresses encountered by maize throughout a growing season? Can these metrics be used to discriminate between hybrids tolerant and susceptible to the stresses they represent? Due to climate change, extreme weather events, such as spells of very high temperature, droughts or torrential rains, are becoming more frequent and sever 2. Very often, these events are causing crop damage and increasing cost for the producers, especially in the USA 3. Altered weather patterns in a specific region are changing temperature and precipitation regimes during the year 4. Under the influence of solar radiation, temperature and precipitation, as the main drivers, crop grows and develops. Extreme weather in the growing season results in environmental stress, affecting plant development. Soil water deficits accompanied by excessively high temperatures are already indicated as the most probable yield limiting factor in maize production in the USA 5. Previous studies showed that daily maximum temperature greater than approximately 30 °C limits maize yields 6,7. Statistical studies of rainfed maize yields indicated two clear features: a strong negative yield response to accumulation of temperatures above 30 °C or extreme degree days (EDD) and a relatively weak response to seasonal r...