LOCATION.--Latitude 41°42'04", longitude 87°59'42", in SE1/4SE1/4 sec. 8, T.37N., R.11E., Du Page County, Argonne National Laboratory (ANL) Reservation, on tower at end of paved road, 400 feet southwest of paved road leading to ANL’s Environmental Research Division Field Site, and 0.2 mile west of Kearney Road.

PERIOD OF RECORD.--

TEMPERATURE: January 1948 to current year.

DEWPOINT TEMPERATURE: January 1948 to current year.

WIND SPEED: January 1948 to current year.

SOLAR RADIATION: January 1948 to current year.

GAGES.--

TEMPERATURE and DEWPOINT: Vaisala HMP45A.

WIND SPEED: Met One Instruments, Model 10B.

SOLAR RADIATION: Black and White "pie" Eppley 50 junction Pyranometer, Model 8-48.

REMARKS.--Data are collected, checked, and published on the World Wide Web by ANL staff. See ANL website (http://www.atmos.anl.gov/ANLMET/) for original data. District staff filled missing periods using data from other gages in the region and adjusted data from prior to 1989 to correct for changes in gage properties. Description of methodology is available in Illinois Water Science Center files. Prior to 1989, gages were located on tower 0.33 mile east of present location.

EXTREMES FOR PERIOD OF RECORD.--

TEMPERATURE: Minimum, -24.9 °F, 7:00-8:00, January 20, 1985; maximum, 101.7 °F, 15:00-16:00, July 13, 1995.

DEWPOINT TEMPERATURE: Minimum, -46.7 °F, 3:00-5:00, January 20, 1985; maximum, 86.0 °F, 13:00-14:00, June 13, 2001.

WIND SPEED: Maximum, 35.3 mph, 12:00-13:00, March 27, 1961.

SOLAR RADIATION: Maximum, 94.1 Langleys per hour, 13:00-14:00, July 3, 1968.