Fresh data from Warren Group shows Massachusetts single-family sales and median prices both dropped 12 percent in April compared to the same month last year.

The price drop was the steepest since Warren started counting in 1987.

As in past months, however, some towns continue to buck the trend. At right is the latest installment of my homemade monthly map showing Boston-area towns where prices failed to fall in April. Topping the list are Winchester, where prices are up 38 percent this year; Brookline, up 20 percent; and Belmont, up 11 percent. (Regular readers will recall that the map shows only towns with at least 10 sales per month -- at least 40 sales so far this year.)

It is worth noting that the number of sales is down pretty much everywhere.

We've talked a lot on this blog about the reasons some towns are better insulated against price declines. The towns on this list -- which, while not identical to the list in previous months, remain fairly consistent -- tend to share a few things in common: Home prices and incomes are higher than for the region as a whole; the local schools are better; the commute to Boston is shorter; and the housing stock is mostly single-family.

Which factors are causal and which are coincidental, I don't know.

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