Only 12% of possible rainfall so far which is good enough to rank 4th driest on record since observations began in 1959
- October rainfall is desperately dry, only 12% of normal and 4th driest of the past 66 years dating back to 1959 at O’Hare Airport.
Best chance for widespread rainfall in over a month
Light showers may arrive late Thursday night, but the heaviest, most concentrated rainfall arrives after midnight and includes the possibility of scattered thunderstorms.
Model simulated radar projections at various times
Forecast GIF showing the chances overnight at seeing lightning and possible thunderstorms, although the greatest chance for thunderstorms will be across the western part of Illinois.
With possible thunderstorms in the forecast, here’s how thunderstorm days typically occur monthly. Only 5% of the typical annual number of thunderstorm days occurs in October
