March 2012 is still the warmest March in Chicago’s records. O’Hare finished the month with an average temperature of 53.5°F. The previous warmest Marches, 1910 and 1945, had averaged 48.6°F, so 2012 broke the record by 4.9 degrees. The National Weather Service calls that the largest gap between first and second place for any record-warm or record-cold month in the city. The month ran 15.6°F above normal. It would have ranked as a warm April.
From March 14 through March 22, Chicago tied or broke daily temperature records on nine straight days. The city had eight days at or above 80°F. Before that March, the Weather Service notes, Chicago had recorded only ten March days of 80°F or warmer in its entire history. The all-time March high, 88°F on March 29, 1986, stayed standing. Everything else about the month felt like the record book had been shoved aside.
False spring is a real operational problem
People opened windows, switched the thermostat to cool, and mentally retired the furnace. Then a more ordinary spring followed, which in Chicago includes nights below freezing well after the daffodils. A furnace that was shut off, with a condensate line left wet, or a humidifier left in summer mode, is a nuisance on the first cold night back. A boiler that was drained or abandoned for the season because “it’s basically summer” is worse.
The other mistake is running heat and air conditioning in the same week without a thought for the house. A warm afternoon and a cold night can both be real. The equipment can follow that if the filter is clean and the thermostat is set to hold a range, rather than being switched off every time the sun comes out. Maintenance belongs on the calendar before this month arrives, so a surprise 80°F stretch is a pleasure and the next 28°F night is boring.
How to treat a warm March
Enjoy it. Leave the furnace or boiler in service until overnight lows are consistently done with freezing, not until the first 80°F day. Schedule the cooling tune-up while the memory of the heat is fresh and the calendar is still open. Wash cottonwood and pollen out of the outdoor coil before June, when the equipment will earn its keep. Our note on what a Chicago summer does to an air conditioner is the other half of this story.
Zima HVAC is in Mundelein. Call (847) 323-8314 to put the spring visit on the books before the first hot week fills the schedule.