There’s a good reason - the period between last bloom and first freeze is longer these days.  Your hives are eating more fall stores after fall blooms end, but before clustering, and far more stores are consumed by an active hive searching for nonexistent blooms than a hive clustering.

The problem is so acute, the USDA had to update their famous map of plant hardiness zones in 2012, and a comparison of the 1990 map with the 2012 map shows the general warming trend, with the warmer zones reaching much further North.

The USDA explains the new map thus:

“The new map is generally one 5-degree Fahrenheit half-zone warmer than the previous map throughout much of the United States.”

So, what’s a beekeeper to do?  No matter how much you feed, you have to verify that your hives don’t lose significant weight before first frost, and if they do, you have to feed some more.

You need to weigh all your hives.