Born in London, Day's first involvement in formal art study was in relation to embroidery and design at the London School of Fashion (1969-71) before completing a Foundation Course at St Martins School of Art. In 1973 she came to Cornwall in order to study Fine Art at the Falmouth School of Art & Design, where she was awarded her BA (Hons).
Her breakthrough into exhibiting was through a solo exhibition at Falmouth Art Gallery in 1998. From that time she has exhibited widely and works from her home studio at Flushing near Falmouth. She is well known for her plant studies and still lifes which are a direct response to the natural world around her.