There is a common belief in northern Australia that (white) people become more aggressive or more suicidal around November. This period is called the Build-up. November is the warmest month in Darwin, although the annual temperature swing is small. More important is the increase of relative humidity in advance of the wet season (the 'Wet'), which is in full swing from mid December till mid March. Therefore the atmosphere becomes very uncomfortable. With this discomfort comes increased irritability and aggression, an attitude known in Darwin as 'troppo'. (The same phrase is sometimes used to describe someone adopting a primitive lifestyle.) Another term is 'mango madness', because that fruit is harvested at the time.
One theory goes that the increasing humidity affects human comfort and hence behaviour. Alternatively, one could blame Seasonal Affective Disorder, a mood change at least in the northern hemisphere related to the annual change of daylength and solar radiation: the depression is relieved by artificial light. Also, a disturbance of sleep patterns may be implicated. Alternatively, aggression or suicide might be related to the anticipated loneliness of those to be left behind when others travel to cooler regions in the approaching holiday season.
However, police records in Darwin and what medical records can be traced show that in fact there is no evidence of any increase of public aggression or suicide during the Build-up. So the idea that people 'go troppo' in Darwin towards the year's end appears to be more a myth than a fact.