KMSP - Spring has officially sprung, and while there’s still plenty of snow and snow piles left on the ground, our atmosphere is definitely starting to warm. While it was a wicked cold start to the month, temperatures have rebounded nicely over the last few days and the Twin Cities has finally hit the 50-degree mark for the first time this year. While we hit that mark a bit later than what’s considered “typical”, we were nowhere close to the record latest.
On average, we hit both 50 and 60 degrees during the month of March with each month after that, hitting another threshold. That means our first 70° usually happens in April, with 80° right around May, and 90° as you get toward June.
But what may be more interesting to note is that our threshold temps are occurring earlier in the 21st century. Looking at records just since 2000, the average date for these threshold temps has crept sooner on the calendar by a solid 1 to 2 weeks on average. The 21st century average first 50° is 9 days sooner, now showing up around the first of March. Both 80° and 90° temps have change the most, both coming in roughly 2 weeks earlier than our overall records that date back to the 19th century.
While climate change is likely at the forefront of your mind when answering the question of why this is occurring, it’s likely more so do to the Urban Heat Island Effect. This is because impervious objects like roads and buildings heat up far more efficiently than soil does. This can cause temperatures to soar faster during the day leading to warmer afternoons over populated areas than what occurs in rural spots. This was very much on display this week when the metro was 2 or 3 degrees warmer on average each afternoon than the much smaller cities around it.