Ramadan, the ninth and holiest month of the Islamic year, is expected to take place between May 15 and June 14 this year, give or take a day. The Islamic calendar is based on lunar cycles, and Ramadan officially begins with the first sighting of the crescent moon. A number of variables, including regional practices, scholarly disagreements and cloud conditions, mean that the start of Ramadan is neither uniform around the world nor perfectly aligned with the Gregorian calendar.
During the month, observant Muslims fast from sunrise to sunset, followed by evening feasting. While most practicing Muslims around the world will use the time to attend mosque more frequently and be with family, the religious fervor of the month will incite a select few to engage in acts of violence in the name of Islam. Jihadists see Ramadan as an especially auspicious time for attacks, believing that actions taken during...