How is gene expression quantitatively regulated? Through the study of how plants perceive and respond to winter, we have discovered that Arabidopsis FLC is an excellent system in which to mechanistically dissect how non-coding transcription and chromatin structure quantitatively regulate gene expression. In the warm, an antisense-mediated chromatin mechanism coordinately influences transcriptional initiation and elongation. With increasing cold exposure, FLC is epigenetically silenced through a conserved Polycomb switching mechanism. The talk will describe our latest understanding of this regulation and how it has been modulated during adaptation.