Variation between temperature and rainfall of recent seasons compared to long-term records is contributing to the general downward trend in wheat production in the summer rainfall region of South Africa. These trends support the theory that the primary summer rainfall period in the South African interior, occurs two months later during the months of January and February prompting the reconsideration of traditional production practises and cultivation season for wheat in the summer rainfall region. This study aims to correlate climatic factors with wheat yield and quality in order to obtain a clearer understanding of the interactions between climate and wheat development. Minimum and maximum temperatures, rainfall as well as cold- and heat units from 2017, 2018 and long-term are compared for seven weather stations across the Free State to identify possible variation in trends. Grain yield, hectolitre mass, protein content and falling number of advanced breeding lines in field trials from the Free State are correlated with these climatic factors in order to identify the effect and critical period of each climatic factor on wheat growth. Long-term rainfall data suggests that the primary rainfall periods historically occurred in November and December for the majority of test localities. The bulk of rainfall in both 2017 and 2018 was however mainly in January and February, suggesting a potential shift of two months over these two years. Our correlations indicate that lower than average rainfall in August to November reduced both grain yield and grain quality of the advanced genotypes. Seasons with substantial rainfall in September to middle October improved grain yield whereas rainfall in October to middle November mostly increased grain quality. Theoretically wheat planted in December and January will have the advantage of high rainfall during seedling development and early plant growth. This benefit may however be neutralised by potentially high heat and low cold units in this period. Additionally, as grain filling and ripening will coincide with cooler temperatures and termination of the rainfall season in May and June, quality and yield might generally be compromised if short-season wheat varieties are not used.