LOCATION.-- Latitude 41°50'37", longitude 88°11'06" (NAD of 1927), in SW1/4SW1/4SW1/4 sec.23, T.39 N., R.9 E., Du Page County, Hydrologic Unit 07120004, on Mack Road 1 mi east of State Highway 59, and located on the north side of the roof of the Blackwell Forest Preserve maintenance building near Warrenville.

PERIOD OF RECORD.--

PRECIPITATION: July 1997 to current year.

GAGE.-- An 8-in.-diameter, unheated, tipping-bucket rain gage.

REMARKS.-- Snowfall-affected data can result during cold weather when snow fills the rain-gage funnel and then melts as temperatures rise. Snowfall-affected data are subject to appreciable errors.

EXTREMES FOR PERIOD OF RECORD.--

PRECIPITATION: Maximum daily total, 5.06 in., September 11, 2000.