The four best links for understanding rain outlook conditions and forecast for Chicago area include the NWS Hourly Weather Forecast, the NWS Chicago Area Forecast Discussion, the NEXRAD radar with motion from wunderground, the darksky radar, (below) …
Hourly Rain, Wind, Temperature Graph …
[Designed for PC/Mac, Tablet but workable on mobile]
Liquid precipitation definitions are listed near the bottom of the page.
+ + + + +
LIQUID Precipitation Form Definitions
Rain and drizzle are the only officially-defined forms of liquid precipitation.
RAIN = Precipitation in the form of liquid water drops that have diameters greater than or equal to 0.5 millimeter. Some define rain with a diameter as small as 0.1 mm.
DRIZZLE = Precipitation in the form of liquid water drops less than 0.5 millimeter.
Rain is classified as …
LIGHT RAIN if rain is falling at a rate between a trace and 0.10 inch per hour;
MODERATE RAIN if rain is falling at a rate between 0.11 to 0.30 inch per hour;
HEAVY RAIN if rain is falling more than 0.30 inch per hour.
Terms such as steady rain, downpour, and torrential downpour are informal uses of rain characteristics, and are not official meteorological definitions. Showers of precipitation are characterized by the suddenness of the start and stop, and by rapid changes in intensity. In certain conditions precipitation (may or may not be visible) falls from a cloud, but evaporates or sublimes before reaching the ground. Liquid precipitation that doesn’t wet the ground is defined as virga and is more often seen in hot and dry climates.
Drizzle is classified as …
LIGHT DRIZZLE if drizzle is falling at a rate from a trace to 0.01 inch per hour;
MODERATE DRIZZLE if drizzle is falling at a rate of 0.01 to 0.02 inch per hour;
HEAVY DRIZZLE if drizzle is falling at a rate of greater than 0.02 inch per hour.
Terms such as misting, spitting, and trickling are informal uses of drizzle characteristics, and are not official meteorological definitions. Mist is a term for small droplets suspended in air, usually associated with fog. “Scotch mist” is an informal term referring to a light steady drizzle.
+ + + + +
SUNLIGHT DATA FOR SECURITY, TRAFFIC SAFETY, AND SPORTS
SunCalc.net data with solar azimuth and trajectory, times for dawn, sunrise, solar noon, sunset, dusk …