Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings. Exams are over, school’s out and youngsters have not yet grown restless in the long summer holidayCredit:Frederick Florin AFP With tricky Brexit negotiations ahead, gloomy economic forecasts and no chance of a Brit winning Wimbledon there may seem little to smile about.But, according to experts today is the happiest day of the year with the UK reaching peak cheerfulness thanks to the good weather, summer holidays and light nights.Dr Cliff Arnall, who coined the term Blue Monday in 2005 to describe the most miserable day of the year – the third Monday in January – used a similar formula to find out when the UK is at its most content.He discovered that July 14th is when well-being soars, as the end of the working week coincides with the beginning of the summer holidays and long warm days allow people to spend more time with friends and family outdoors. The new formula was commissioned by Jury’s Inn who have developed a Stay Happy Guide for guests. Dr Arnall said: “The start of the school holidays has a positive effect on the household. Family stress can be significantly reduced as the usual hassle of getting children ready for school then joining the rush hour school traffic stops during the holiday period. Key for the formula Teenagers who have taken exams in May and June are also feeling much calmer by July as schools and colleges close for the summer and results are over a month away.The cabin fever associated with the end of the six week break is also many weeks away and children have not had enough time to get bored and restless. “This reduction in traffic congestion also benefits people without children, or whose children have grown up, as the roads are clearer and car trips are more relaxed.”Previous studies have found that happiness rockets on Fridays, as levels of stress hormone cortisol fall gradually throughout the day with the approach of the weekend. The formula The new formula factors in emotional connectedness, kindness, health, being true to yourself, calmness, uncertainty, friends, family and fun. Crucially it does not include financial wealth after several studies have shown that money does not make people happier.“The world today is a very different place to 2005,” said Dr Arnall, 51, a from Brecon, Wales, a former lecturer at Cardiff University who now runs happiness and confidence sessions for organisations including the Department for Work and Pensions and the NHS.“We are now in a time where massive socio political national and international changes force us to examine where we are heading.“The formula addresses the core human fundamental issues head on to help people build and maintain their happiness and well-being in spite of a very uncertain world.”This year’s Blue Monday, which fell on January 16, was deemed to be the most depressing ever because of a string of celebrity deaths, anxiety of Brexit and fears about the Donald Trump presidency in the US. The gloom was compounded by bad weather and Christmas debts.