[en] This document presents the climatological data measured at the U. S. Department of Energy's Hanford Site for calendar year 2001. Pacific Northwest National Laboratory operates the Hanford Meteorology Station and the Hanford Meteorological Monitoring Network from which these data were collected. This report contains updated historical information for temperature, precipitation, normal and extreme values of temperature and precipitation, and other miscellaneous meteorological parameters. Further, the data are adjunct to and update Hoitink (and others) (1999, 2000, 2001) and Hoitink and Burk (1994, 1995, 1996, 1997, 1998); however, data from Appendix B--Wind Climatology (Hoitink (and others) 1994) are excluded. Calendar year 2001 was slightly warmer than normal at the Hanford Meteorology Station with an average temperature of 54.3 F, 0.7 F above normal (53.6 F). The hottest temperature was 106 F on July 4, while the coldest was 16 F on December 25. For the 12-month period, 8 months were warmer than normal, and 4 months were cooler than normal. Precipitation for 2001 totaled 6.66 inches, 95% of normal (6.98 inches); calendar year snowfall totaled 15.1 inches (compared to the normal of 15.4 inches). Calendar year 2001 had an average wind speed of 7.6 mph, which was normal (7.6 mph). There were 31 days with peak gusts (ge)40 mph, compared to a yearly average of 27 days. The peak gust during the year was 69 mph on December 16. November 2001 established new records for both days and hours with dense fog (visibility (le)1/4 mile). There were 14 days and 99.4 hours of dense fog reported, compared to an average of 5.5 days with 22.0 hours. The previous record was 13 days in 1965 and 71.4 hours in 1952. The heating-degree days for 2000-2001 were 5,516 (7% above the 5,160 normal). Cooling-degree days for 2001 were 1,092 (8% above the 1,014 normal)