Summer sunlight helps to trigger a seasonal rise in suicides, claim UK researchers.
Suicide rates peak in the May sunshine
The Priory Group says more people take their lives in May than in any other month, which could be down to the climate.
The extra sunshine, which helps combat depression, may also provide the people the energy they need to act on their suicidal feelings, they believe.
There is one suicide every 84 minutes in UK and Ireland.
Around 6,300 people take their lives each year, the Priory Group said.
Professor Chris Thompson, the group's director of healthcare services, said research showed there was a direct link between the amount of sunshine and the national suicide rate.
In Scandinavia and Canada, studies have shown that those who commit suicide have low levels of a "happy" brain chemical called serotonin.
Others have shown that serotonin levels often rise with the amount of sunlight a person is exposed to.
Professor Thompson said: "It is a harsh irony that the partial remission which most depression sufferers experience in the spring often provides the boost of energy required for executing a suicide plan.
"People coming out of depression have a higher suicide rate than those who are severely depressed and this is exacerbated by the season.
"Spring is a time for new beginnings and new life, yet the juxtaposition between a literally blooming world and the barren inner life of the clinically depressed is often too much for them to bear," he said.
A spokeswoman from the Samaritans said there definitely was a rise in suicide rates in spring/summer.
She said a number of factors might be involved, such as changes in body clock and social interactions.
Figures show there has been a 50% rise in attempted suicides since 1990. Most suicides are among men.
Amelia Mustapha from the Depression Alliance said: "Depression is a debilitating, life-threatening disease which affects one in five people at some stage in their lives.
"Unfortunately, depression is still under-diagnosed, which means that hundreds of thousands of people in the UK are trapped in the throes of this potentially-fatal illness.
"We urge anyone who feels suicidal, or who believes that they are seriously depressed, to visit their GP for help.
"The good news is that depression can be successfully treated and many affected by the condition go on to lead happy and fulfilling lives."