Summary: January in Illinois finished out at 26.7 degrees, 0.3 degrees above average. Both precipitation and snowfall were below average. The statewide average precipitation (rain plus water content of snow) was 0.85 inches, 1.22 inches below average. Snowfall was below average across most of the state.
The temperatures in January in Illinois showed some very large swings that tended to cancel each other out in the end since we finished 0.3 degrees above average. The first 9 days were above average, followed by 4 days below average, then 3 days above average. The second half of January started out much below average, but steadily warmed and by the end of the month was 20 degrees above average.
While the magnitude of the swings were impressive, the pattern of warm and cold stretches is typical of winter in Illinois and represents the passage of warm and cold fronts across the region. Because it may take a day or more for a system to pass through Illinois, the dates and size of the temperature departures at a particular station may not correspond to the statewide numbers, especially in far southern Illinois.
The January precipitation (left) and departures from average (right) show that precipitation was uniformly light across Illinois, just under an inch in most places (light green) and just over an inch below average (shades of yellow).
The January snowfall (left) ranged from 2 to 5 inches in most locations. Western Illinois saw 5 to 7.5 inches. However, as the panel on the right indicates most of Illinois received below-average snowfall (shades of beige and yellows).
October ended up warmer and drier than average in Illinois. The statewide average temperature was 55.8 degrees, 1.7 degrees above average.
The statewide average precipitation was 1.47 inches, 1.79 inches below average and the 22nd driest October on record. Even so, there were a few areas on the border with Iowa and Kentucky that received 2 to 3 inches of precipitation (dark blue in map below). The two largest monthly totals came from Stockton IL (COOP) and Orion IL (IL-HY-1), both reporting totals of 3.47 inches of precipitation.
The outlook for November, according to the National Weather Service, shows an increased chance for above-average temperatures across Illinois and the Midwest. The outlook shows an increased for above-average precipitation for the southern two-thirds of Illinois. This is part of broad area of expected wetter conditions across the southern US. Meanwhile, the northern third of Illinois has equal chances (EC) for above, below, and near-average precipitation. Click on the maps to enlarge.
Here is the rainfall map for the past 7 days. Most of the rain in Illinois has come in the last 2 days of that mapping period. In fact, almost all the rain in October for Illinois has fallen in the last 2 days.
Most of Illinois was in the two lighter shades of green, indicating rainfall amount of between 0.5 and 1.5 inches. There is a hole in southwestern Illinois (blue) were rainfall amounts were less than 0.5 inches. Higher amounts of 2 or more inches just missed Illinois, and fell across the border in Kentucky and southern Indiana.
It looks like we have one last shot of rain in October on Saturday.
August was cool across the state and dry in most places in Illinois, capping off a summer that was cool and wet.
The statewide average precipitation for August in Illinois was 2.95 inches, 0.64 inches below average. However, this was followed by a very wet June with 9.44 inches, and a wet July with 4.84 inches. As a result, the summer precipitation total was 17.23 inches. That was 5.36 inches above average and the 6th wettest summer on record.
Here are the top ten wettest summer in Illinois. It was wetter than last summer and 2010, but nearly an inch away from the incredible summer of 1993.