It is an unfortunate circumstance that contemporary climate analysis focuses almost exclusively on average conditions, at the expense of their variance. For example, it is easy to find on the Web that today’s climatological average high temperature in Boston is about 68 F (20 C), depending on the exact time interval over which the average is taken. However, if you want to estimate the climatological variance of today’s high temperature, you have to piece together the observational data and do the calculations yourself. The results of such an exercise are actually quite interesting, since like the average high temperature, the high temperature variance has a pronounced seasonal cycle. It turns out that September is the month with the lowest high temperature variance, and April the month with the highest variance (at roughly twice the September value). This relative consistency of September weather, along with the rather pleasant average high temperature, makes it perhaps the most agreeable month of the year.
Today: Showers likely, especially around midday. Some showers may contain brief downpours and strong winds. High 69 F (21 C).
Tonight: Decreasing clouds, much cooler. Low 46 F (8 C).
Saturday: Mostly sunny. High 62 F (17 C).
Saturday night: Partly cloudy. Low 49 F (9 C).
Sunday: Mostly cloudy, with a chance of showers late. High 62 F (17 C).
Monday: Mostly cloudy, a few showers possible. High 64 F (18 C).