Seasonal crime component.

<p>A comparison between the raw crime data and the SSA seasonal component (grey) for Houston (blue) and Los Angeles (red). The trend is subtracted from the data and then the data is smoothed using a moving window average. As the oscillations are related to the total amount of crime, the data and seasonal component have been divided by the trend pointwise in time to normalize the oscillations. Note that the seasonal oscillations are on the same order compared to the trend level of crime across all crime types. Even when the level of crime is low, a fairly consistent oscillation is seen. Note the large aberration in the Los Angeles data just after the 2008 crash. Such social catastrophes can override any seasonality and lead to dramatic changes in future crime rates.</p

Los Angeles temperature data.

<p>In the top panel, the daily average of high and low temperature for Los Angeles is plotted in red. The green curve is the SSA trend, and the dark green curve is the seasonal component plus the trend. In the bottom panel, the seasonal component alone is shown. The temperature variations in Los Angeles are extremely regular, though the summer of 2006 does appear unusually warm. The aberrations in crime seasonality are far larger, and less consistent than the temperature variations.</p