London - For some it reflects their downbeat mood as the working week begins, for others it is a way to get themselves in the right frame of mind.
But women are more likely to wear black on a Monday than any other day, according to research.
They generally dress in darker colours early on but then brighten up their clothes as the week goes on.
A study of 2 000 women carried out by Tu at Sainsbury’s to mark the tenth anniversary of the supermarket chain brand also found that one in five pick different colours for different days.
The feeling that bright clothes reflect a happier outlook and have the ability to lift mood was the strongest reason cited for choosing colourful outfits ahead of the weekend.
Anna Clarke, head of womenswear buying for Tu at Sainsbury's, said: “The links between colour and mood are well established and looking vibrant can encourage the same feeling in the wearer.
“Black clothing will always have its place but embracing colour and being adventurous with your style can have added bonuses on our happiness levels.
“Whatever the essentials a woman swears by, the results show that finding your confidence and the colours that work for you only grows with age.”
The study also found that black is currently the most-worn colour, followed by blue.
It also emerged that the choice of a black outfit can boost a woman's confidence. The second most popular confidence-boosting colour is red.
The study also discovered a woman's clothes confidence grows with age. As well as colours and confidence, the research also examined the dramatic changes in fashion over the last ten years and revealed women's favourite fashion innovations.
Skinny and slim cut jeans came top followed by ultra high heels, large handbags and big sunglasses.
Wearing trainers for fashion rather than sport or exercise also made the list.
Bolder prints, clashing prints, oversized jumpers and bright colours also made the hall of fame.
And while trends are always changing, some things really do stand the test of time - six in 10 women have an item of clothing they've owned for more than 10 years, results showed.
The study of fashion attitudes also found certain items transcend time and compiled women's top 20 wardrobe essentials - a black cardigan emerged as the most voted for item followed by a little black dress and skinny jeans.
A maxi dress and a push-up bra were also deemed to be “must-haves” for any modern woman's clothing repertoire, while denim jackets, neutral wedges and a white shirt can also be found among the top 20 wardrobe essentials.
Ms Clarke added: “The study shows the strength of correlation between how a woman feels and the colours she chooses to dress herself in.
“Black is a very versatile colour and can help generate a working mind-set as the results clearly show but it's interesting to see that when it comes to feeling good and more positive a splash of colour really does make the difference.
“There was a clear trend towards wearing more colour towards the end of the week and a visible boost to a woman's mood when wearing brighter colours.” - Daily Mail