The years between January 1997 and December 2006, were divided into 120 months with a 'month' categorized as a unit. Then the mean temperature of each month was calculated. The correlations between the number of patients with active SLE and the mean temperature in the same month were analyzed; it was found that there was a significantly inverse correlation between both (r = -0.352, p,0.001, Figure 2 and Table 1 ).