This file provides the latest status of NOAA's 1981-2010 Climate Normals Created: June 29, 2011 Last Modified: August 21, 2015 *** August 21, 2015: Service Pack 2 (SP2) of NOAA's U.S. Climate Normals has been released. SP2 includes changes to precipitation, snowfall, and/or snow depth parameters for the following 8 stations: USW00014735 USW00013904 USW00023157 USW00003927 USC00053146 USC00195984 USW00094197 USW00013959 Changes for the 8 stations above were requested by representatives of the National Weather Service. No further changes to existing 1981-2010 Climate Normals products are expected. *** August 21, 2015: A new file has been added to the "station-inventories" directory that contains zip code and post office names for the vast majority of stations included in the 1981-2010 Climate Normals. In addition, the daily standard deviation files (for minimum, maximum, and mean temperatures as well as diurnal temperature range) have been replaced using the methodology described by a forthcoming paper by James and Arguez in the Journal of Atmospheric and Oceanic Technology. The new methodology computes daily standard deviations from climate anomalies within the 15-day window, where the climate anomalies were computed using daily temperature normals. The previous method re-centered each day within the 15-day window using the raw daily mean for that day. The net effect of this methodological change, on average, for all stations and all parts of the year, is close to zero, with only ~5% of values changing by more than +/- 0.2F. *** August 17, 2015: This update to NOAA's 1981-2010 Climate Normals replaces the hourly normals products. The files were replaced to (1) add more stations to the hourly product line and (2) modify the computation of the percentage of calm winds. See the addendum in the documentation directory. In addition, new supplemental products are being released, including 10-year hourly normals and air freezing index values and return periods. See the supplemental directory for more information and to access these products. In the future, we plan to release various new monthly temperature normals products (5-, 10-, 15-, 20-year averages; OCN; and Hinge Fit) computed using something other than a 30-year average. *** January 2, 2013: NOAA's 1981-2010 Supplemental Normals were released on January 2, 2013. This includes growing degree days, probabilities of first and last frost and freeze events, probabilities of occurrence of minimum temperature thresholds, and growing season length probabilities. See readme.txt and the "supplemental" directory for more information on how to access these new products. *** August 4, 2012: Effective Saturday, August 4, 2012, Service Pack 1 (SP1) of NOAA's U.S. Climate Normals is being released. SP1 includes the following 4 changes: 1. Following change requests submitted by the National Weather Service (NWS), the precipitation, snowfall, and snow depth normals parameters at 83 stations were recalculated based on GHCN-Daily version 2.92-upd-2012052822. These include 81 stations for which the NWS submitted additional snowfall and snow depth data. The normals for the other two stations were reissued to remedy unique issues affecting their average monthly precipitation totals in particular months. All other normals remain unchanged and are based on GHCN-Daily version 2.80-por-2011052713. The stations whose precipitation- and snow-related normals were recomputed are listed below. Station ID Reason/Action ----------- ----------------------------------------------------------- USW00003017 July precipitation normal was suboptimal due to problematic input data; improved by using only Denver Stapleton for underlying estimated monthly totals USW00003103 NWS supplied additional snow data USW00003859 NWS supplied additional snow data USW00003928 NWS supplied additional snow data USW00003940 NWS supplied additional snow data USW00003945 NWS supplied additional snow data USW00004781 NWS supplied additional snow data USW00012816 NWS supplied additional snow data USW00012916 NWS supplied additional snow data USW00012921 NWS supplied additional snow data USW00013722 NWS supplied additional snow data USW00013723 NWS supplied additional snow data USW00013728 NWS supplied additional snow data USW00013733 NWS supplied additional snow data USW00013741 NWS supplied additional snow data USW00013743 NWS supplied additional snow data USW00013764 August precipitation pseudonormal was sub-optimal due to insufficiently representative input data; enough data now available for computing traditional normals rather than pseudonormals USW00013865 NWS supplied additional snow data USW00013870 NWS supplied additional snow data USW00013878 NWS supplied additional snow data USW00013889 NWS supplied additional snow data USW00013894 NWS supplied additional snow data USW00013897 NWS supplied additional snow data USW00013899 NWS supplied additional snow data USW00013958 NWS supplied additional snow data USW00013962 NWS supplied additional snow data USW00013964 NWS supplied additional snow data USW00013966 NWS supplied additional snow data USW00013967 NWS supplied additional snow data USW00013968 NWS supplied additional snow data USW00013970 NWS supplied additional snow data USW00013994 NWS supplied additional snow data USW00014607 NWS supplied additional snow data USW00014732 NWS supplied additional snow data USW00014734 NWS supplied additional snow data USW00014745 NWS supplied additional snow data USW00014764 NWS supplied additional snow data USW00014821 NWS supplied additional snow data USW00014847 NWS supplied additional snow data USW00014852 NWS supplied additional snow data USW00014860 NWS supplied additional snow data USW00014891 NWS supplied additional snow data USW00014895 NWS supplied additional snow data USW00014922 NWS supplied additional snow data USW00014926 NWS supplied additional snow data USW00014929 NWS supplied additional snow data USW00014933 NWS supplied additional snow data USW00014935 NWS supplied additional snow data USW00014946 NWS supplied additional snow data USW00022010 NWS supplied additional snow data USW00023007 NWS supplied additional snow data USW00023023 NWS supplied additional snow data USW00023034 NWS supplied additional snow data USW00023065 NWS supplied additional snow data USW00023154 NWS supplied additional snow data USW00023161 NWS supplied additional snow data USW00024025 NWS supplied additional snow data USW00024036 NWS supplied additional snow data USW00024132 NWS supplied additional snow data USW00024137 NWS supplied additional snow data USW00024138 NWS supplied additional snow data USW00024143 NWS supplied additional snow data USW00024144 NWS supplied additional snow data USW00024152 NWS supplied additional snow data USW00024230 NWS supplied additional snow data USW00024243 NWS supplied additional snow data USW00093721 NWS supplied additional snow data USW00093738 NWS supplied additional snow data USW00093808 NWS supplied additional snow data USW00093815 NWS supplied additional snow data USW00093993 NWS supplied additional snow data USW00094012 NWS supplied additional snow data USW00094702 NWS supplied additional snow data USW00094728 NWS supplied additional snow data USW00094789 NWS supplied additional snow data USW00094814 NWS supplied additional snow data USW00094822 NWS supplied additional snow data USW00094823 NWS supplied additional snow data USW00094830 NWS supplied additional snow data USW00094846 NWS supplied additional snow data USW00094847 NWS supplied additional snow data USW00094849 NWS supplied additional snow data USW00094910 NWS supplied additional snow data 2. Higher-precision heating and cooling degree day normals (to the hundredths place) are now provided in addition to the regular-precision normals (whole degrees). See #4 below for more information. 3. The station lists on the NCDC FTP site has been updated to reflect NCDC's latest metadata on station locations and names. Station USW00092762 (a Pennsylvania station known as "Site R") has had its GHCN-Daily ID corrected to USW00093762 recently, but at the moment we have kept this station's ID as USW00092762 in SP1. This and other known ID issues are scheduled to be addressed in a future service pack. 4. The "station" subdirectory under products has been moved into a new directory called "auxiliary" which also contains a new subdirectory entitled "high-precision-degree-days" that contains the new values described in item #2 above. These changes are reflected in the modified readme.txt file. *** September 1, 2011: In order to fix a minor bug, the following 4 files have been replaced in www1.ncdc.noaa.gov/pub/data/normals/1981-2010/products/precipitation/ : mtd-prcp-normal.txt mtd-snow-normal.txt ytd-prcp-normal.txt ytd-snow-normal.txt For precipitation, the change affects the average month-to-date and year-to-date totals in one month at each of 37 stations, representing 0.03% of all station-months. For snowfall, the change impacts a total of 427, or 0.56%, of the station-months at 422 stations. Accordingly, the affected individual station normals files have also been replaced in www1.ncdc.noaa.gov/pub/data/normals/1981-2010/products/station/ In exceedingly rare instances, the month-to-date (or year-to-date) totals could actually decrease by a very small amount from one day to the next. This was an artifact of an algorithm used to smooth the totals through the year and only occurred when the corresponding average monthly total was -7777, i.e., in less than 0.005 inches of precipitation or 0.05 inches of snowfall. *** July 7, 2011: A file documenting the format of the filled monthly precipitation data (source-datasets/mly-prcp-filled.txt) has been added in the documentation subdirectory. See the readme.txt file for specifics on filenames. *** July 1, 2011: These normals were released on July 1, 2011. This includes annual, seasonal, monthly, daily, and hourly normals for over 9800 stations. Later installments will include climate division normals, agricultural-related normals such as frost-free dates and growing degree days, as well as population-weighted heating and cooling degree days.