Sunday's official high temperature of 33 degrees at O'Hare International Airport stands as a milestone in Chicago weather history.
It marks the 309th consecutive day on which the city's high temperature rose to at least 32 degrees, surpassing the long-standing record of 308 consecutive days at or above 32 degrees recorded in 1878.
With luck, Monday's high temperature -- predicted to be in the low 30s but above freezing -- will extend the consecutive string to 310 days, after which the bottom drops out and temperatures plunge on the first day of the new year.
The record surpassed Sunday is one of a number of rare weather occurrences we are experiencing so far this winter, according to the National Weather Service.
Among them are:
Chicago's high temperature hasn't been below freezing this winter, the latest that has occurred since Jan. 1, 1924. If the daily high stays above 32 degrees until Wednesday, that'll be a new record.
In 2011, there have been 354 days with a high at or above 32 degrees, the most since calendar year 1931, when there were 355 days with a high at or above freezing.
It's been 310 days since Chicago has had an official snowfall of at least an inch on a single calendar day. We went 315 days with that inch of snow in 1958 and 319 days in 1940.
It has been 308 days since Chicago has officially had an inch of snow cover on the ground. The only time that has happened before is in 1940, when Chicago went 313 days without that inch of snow cover.
The next chance for snow in the area, according to ChicagoWeatherCenter.com, is maybe Thursday or Friday.