For the past three days – Friday through Sunday – the high temperatures (F) here in Chicago have been 65, 70, and 62. It has been spring, essentially. Those numbers might make people in the South want to grab the parka; here they had me and most of the city heading outside in shorts and t-shirts. It was great. It was also, of course, totally bizarre. February is the traditional month for weather that makes you want to drink bleach in Chicago. February is the month during high school in which we could count on a cancellation or two per year because the pipes were frozen. February in Chicago is gray, cold, windy, and miserable. I'm convinced that the term "blustery" was invented by someone standing outside here in February.
Since the winter has been warm as a whole, this weekend alarmed more than a few people. It's great, but…what gives? For giggles, I spent 15 minutes finding old National Weather Service data for Chicago in February dating back to 1990. The year is arbitrary and represents the limit of how much I cared to continue looking up older years. For each year I plotted the highest and lowest temps recorded in February as well as the monthly mean temp. Here's a quick chart followed by a table showing the same data:
This oddly warm weather is definitely on the upper end of normal for the past three decades, but it's hardly unusual. The 2017 data, as the table shows, are almost identical to, for example, 1999. Compared to more recent very cold years like 2014 and 2015, this year is bizarrely warm. It's not the only unusually warm February to be found in the recent past, though.
The point is not that "Climate change is fake, man!" Mountains of data demonstrate that it is a well-supported phenomenon. My point is that our memories are extremely unreliable when it comes to remembering ephemeral things like this. I was alive in 1999 (obviously) and I have zero recollection of that warm winter. None. In my mind, what is happening right now is exceptional because February, as I and most people in this area think, is the bone-chilling cold month. It's the peak of winter misery. When we think things like, "Man, the weather is never like this in February!" we're relying on our perception of something we don't actually remember. Nobody actually remembers the weather, save perhaps some kind of Rain Man-esque savant.
In short, our anecdotal evidence for or against changes in climate are not only irrelevant, but also very likely to be imaginary anyway. It is interesting for me to see just how wrong my recollection was, even as someone who generally pays attention to these things. It's a good reminder to stop giving credence to our own impressions and instead to stick to the actual data.