Spring is a time when most people's spirits are soaring after the long winter. But statistics show that in the U.S. it can also be deadly. Over the years, a number of bloody massacres have all occurred in April.

The Oklahoma City bombing, massacres at Columbine High School and Virginia Tech University, and just recently, an incident in which a killer in a quiet New York town fired 99 shots, killing 13 people – all took place in the fourth month of the year.

It appears that as the seasons change, so do people’s mindsets, and for those who are alienated and depressed, April showers don’t always bring May flowers as they proceed to harm not only themselves, but others as well.

“The people who commit these crimes are obviously very disturbed people. In April, when things are starting to get warmer, people are starting to socialize. It’s in their faces, and it ignites this spark of latent resentment and so you see these things happening,” clinical psychologist Drew E. Permut believes.

But you can’t blame everything on April.

Many Americans see part of the problem as having too many guns in the hands of citizens, while others, such as legal policy analyst Dave Rittgers, think there is a much more dangerous weapon: the media. Getting even a drop of media attention creates a copycat effect, which is now resulting in more shootings all over the world.

“I think the press cycle that we have reinforces whatever motivates some of these people to do what they are doing, that giving them coverage and attention spurs people who for whatever reason do these things,” Rittgers says.