You are farther north than me (near Bloomington), but I tapped last week and am anticipating a big run that hopefully started today, and with temps here in the 40's and low 50's with freezing at night it should be good...I typically tap when I see a forecast of more than 4 days in a row over 40. This is the earliest I have tapped, but I missed a couple of runs last year, so I'm playing the better safe than sorry game. Good luck!
2014 - 8 taps, turkey fryer, 130 gallons sap, just under 2.5 gallons syrup.
2015 - 50 taps and counting.
2016 - 60 taps on 3/16 and a Bill Mason evaporator on order.
2017 - 115 taps on 3/16, homemade r/o.
2018 - 150 taps on 3/16, r/o a big help, but lots of leaks killing yield.
2019 - sticking with 150 taps or maybe less, focusing on good vacuum and less waste to increase yield. Doubling up my r/o, and made a vacuum filter that looks promising.