Influences on violence

Top 11 days of "violence against the person" incidents in London in 2009

Bottom 10 days of "violence against the person" incidents in London in 2009

Most police officers would agree, I think, that the biggest influence on violence is alcohol. I have used a Met Office website to look at weather conditions in 2009 that can be found here. Weather appears to influence violence through the mechanism of more excessive alcohol consumption, I think, when it is hot. This hypothesis is supported by the fact that the peak time for incidents is around midnight. Holidays such as New Year and hot bank holiday weekends that co-inside with half term seem add to the mixture. Halloween and extra hour at night due to changing the clocks also seems to affect things.

There appears to be a background level of violence of about 300 incidents a day (I am sure that 22/6/09 is a data blip due to the computer being out of action for about 16 hours)  that is undeterred by anything including snow.

There is an interesting paper "The influence of weather on local geographical patterns of police calls for service." in Planning and Design 2009 Volume 36 Number 5. This looked at various weather factors and concluded that there was a relationship between weather temperature and disturbance incidents. The methodology looked at the temperature at the time of the incident. From my brief analysis I think that the influence of temperature continues even after it becomes cooler due to the alcohol factor.