The December 2015 temperature anomaly for Grand Rapids, Michigan, was a staggering +9.9 degrees F, almost twice the size of the November anomaly of +5.4 degrees F.
Heading into December, the cumulative anomaly for 2015 through November stood at -11.7 degrees F, so thanks to El Nino the massive negative anomaly for 2015 is all but wiped out, erasing 92% of the 22.6 degrees of negative temperature anomaly in just four months.
The year 2015 thus finishes with a total anomaly of -1.8 degrees F. That's basically an undetectable .0049315 degrees F below normal on your average day in 2015.
Precipitation in December, unsurprisingly, was 33% above normal while snowfall was just 2.5 inches, 84% below normal. Mean snowfall for December going back to the beginning of the record is 15.7 inches.
