With temperatures like this, it doesn’t take long to get cold. But as far as cold blasts go, this one is rather weak. Last night’s low temperature (January 28th) didn’t even fall below zero in Green Bay. In fact, the coldest temperature all winter has been -5°. It occurred twice in early December. .. In comparison to the previous 5 winters, there is a stark difference.

Figure 1. Coldest Temperatures

As shown in the graphic above, last winter’s coldest temperature was -21° – which wasn’t even a record.

Green Bay’s coldest temperature ever was -33° on February 10th, 1899. The coldest temperature in Wisconsin was -55°, on February 4th of 1996, in Couderay in the northwestern part of the state. That was the same cold snap in which the temperature didn’t rise above 0° for 5 consecutive days here in Green Bay.

Figure 2. Nights below 0° up till January 28

The mercury has only dipped to or below zero 8 times this winter. Compare that to last year when temperatures dropped to or below zero 31 different times from December through January 28. On average there are 14 to 15 nights below zero up to this point. That’s a lot of cold days and it doesn’t even account for February and the beginning of March.

Figure 3. Avg. Nights Below 0° All Year

The graphic above displays, the average amount of nights below zero during an entire year. In Green Bay, we typically see 20 to 25 nights below 0°. Meanwhile, places like Antigo can see more than 40 nights below zero. In other words a 2 hour drive can make a huge difference. That difference would be even greater if you were traveling from the lakeshore to the northwoods. The warmer waters of Lake Michigan tend to keep those communities warmer at night. The reason being is that water doesn’t cool off as quickly as land.

With all of these statistics in mind, I have a few more for you. Back in December, we had 3 consecutive nights below zero, but last year we had a stretch of ten nights below 0°. Again this goes to show that our cold snaps this year haven’t been to extreme.

Figure 4. Consecutive Nights Below 0°

One interesting point to be made on this graphic is the stretch of 9 consecutive nights below zero in 2006-07. This actually occurred in February of that winter. Compare that to Figure 2 which shows through January 28, in 2006-07 the temperature only dropped to or below zero once. In other words, it was a mild start to the year, with a brutally cold blast in February, something that isn’t all too uncommon.

Of course when you have these frigid temperatures at night, the mercury doesn’t always recover during the day. Today (January 28) was the second day this winter with highs only in the single digits. In fact today’s high of 8° was the coldest all year. Tomorrow’s highs will be back into the lower teens, which means we won’t see consecutive days with highs only in the single digits.

Figure 5. Consecutive days in the 0's or colder

As shown in Figure 5, there was a stretch of 4 consecutive days last winter in which the temperatures didn’t rise into the teens. A similar stretch has occurred three other times in the past 5 winters, meaning these brutal cold snaps usually don’t last much longer than 4 or 5 days.

Often times, during these cold snaps, the temperature won’t even rise above 0° That has occurred 4 times in just the past three years. While it hasn’t happened yet this winter, we have a lot of cold days ahead of us.

Figure 6. Days Below 0°

Until Next Time,
Meteorologist Andrew Thut