How many 60-degree days, on average, do we usually have by now?

Dear Tom,
We’ve had so few 60-degree days so far this year. How does this year’s tally compare to the average and recent years?
— Pat Byrne, Hoffman Estates
Dear Pat,
Since 1871, Chicago has logged temperatures in the 60s in all 12 months, and the long-term average number of 60-degree days through April 4 is five. This year, the city has logged just three, all in February — a high of 60 on Feb. 19, 66 on Feb. 20 and 62 on Feb. 27.
There have been 11 years without a 60-degree day through April 4, most recently 1980 and 10 with just one, the last ones in 2013 and 2014. There have been some banner warm years, most notably 2012, that logged 23 such days. Other years with an abundance of early-season warmth include 1976 and 1945, both with 19; 2000 with 18; and 1910 and 1946 with 17. Last year by this time, the city had racked up 13 days with highs of at least 60 degrees.