In “Natural haplotypes of FLM non-coding sequences fine-tune flowering time in ambient spring temperatures in Arabidopsis" Lutz et al. address the biological relevance of FLM splice variants for variation in flowering time in natural accessions and identify non-coding sequence polymorphisms that contribute to the regulation of basal expression levels and the differential, thermo-responsive generation of the β and δ splice variants. As such, this work provides novel insights into the regulation of flowering in the ambient temperature range and manages to dissect polymorphisms which are relevant for basal FLM expression and temperature-induced effects on the β and δ splice variants.