XM ACIS (great for looking up climate records at a variety of different locations, great interface)
ThreadEx site to ID ThreadEx cities and learn thread histories
Wolfram Alpha: Type in "Weather in [city], on [date]" to get historical weather data)
Iowa State Automated Data Plotter - Notable Apps: **#82 Calendar of Daily Observations (can do daily average temp. departure, **#43 Recent (Past 2-3 Days) Timeseries/Meteogram (Temp/Winds/Pressure/Clouds/Visibility), #66 Consecutive Days with High/Low Temp Above/Below Threshold, #49 Daily Frequency of Some Threshold (snow, precip, temps), #168 Latest Date of Year for High Temperature, #34 Max Stretch of Days with High/Low Above/Below Threshold, #62 Daily Snow Depth (shows entire history/all winters in one chart of site you choose), #25 Distribution/Spread of Daily High/Low Temperatures (by state for specific date), #132 Top 10 Precip./Temp. Values by Month/Season (ex.: shows when the most precip. ever fell or when the temps were highest/lowest over a certain number of consecutive days), **#172 Accumulated Year to Date Precipitation (compared to average) (can also add other years to graph), #180 Daily Temperature Climatology
Archives:
WPC Surface Analysis Archive (over the past 12 years - includes map in 3 hr. intervals for each day)
Daily Weather Maps Archive (over the past 17 years)
NOAA Central Library U.S. Daily Weather Maps Archive (back to 1871)
**UCAR Image Archive (radar, satellite, sounding, surface, & upper air data/images/loops each day since 1996)
U of Wyoming Sounding Archive (GIF, PDF, or text format) from across North America since 1973
State College NWS Past Weather and Climate Homepage (access records, normals, climate graphs, etc.)
Historical Tropical Weather Events (organized by year for both Atlantic and Pacific since 1998)
NOAA Storm Events Database (since 1950) (records from all sorts of weather events for specific date range)
COOP Site Observation Records through NOAA
NCEP Reanalysis Data
SPC Mesoanalysis Archive, SPC Main Archives Page
Historical SPC Severe Weather Database of storm reports
Climate Centers:
High Plains Regional Climate Center (ACIS Climate Maps)
Northeast Regional Climate Center
Midwestern Regional Climate Center (CLI-MATE LOGIN)
Southeastern Regional Climate Center (Climate Perspectives Maps By Region)
Maximum wind gusts over past 5 days by state
NOAA Air Resources Labratory: HYSPLIT (track air parcels)
30-day loop of analyzed 200-hPa heights and anomalies worldwide (CPC)
Global Circulation Animations: Means and Anomalies (past 1,7,30,90,365 day loops)
Past 5 Days Satellite Images and Loops, Past 7 Days Satellite Movie
Intellicast Yesterday's Radar Loop
Archives: NEXRAD (select from NWS radars), Plymouth State
ThreadEx site to ID ThreadEx cities and learn thread histories
Wolfram Alpha: Type in "Weather in [city], on [date]" to get historical weather data)
Iowa State Automated Data Plotter - Notable Apps: **#82 Calendar of Daily Observations (can do daily average temp. departure, **#43 Recent (Past 2-3 Days) Timeseries/Meteogram (Temp/Winds/Pressure/Clouds/Visibility), #66 Consecutive Days with High/Low Temp Above/Below Threshold, #49 Daily Frequency of Some Threshold (snow, precip, temps), #168 Latest Date of Year for High Temperature, #34 Max Stretch of Days with High/Low Above/Below Threshold, #62 Daily Snow Depth (shows entire history/all winters in one chart of site you choose), #25 Distribution/Spread of Daily High/Low Temperatures (by state for specific date), #132 Top 10 Precip./Temp. Values by Month/Season (ex.: shows when the most precip. ever fell or when the temps were highest/lowest over a certain number of consecutive days), **#172 Accumulated Year to Date Precipitation (compared to average) (can also add other years to graph), #180 Daily Temperature Climatology
Archives:
WPC Surface Analysis Archive (over the past 12 years - includes map in 3 hr. intervals for each day)
Daily Weather Maps Archive (over the past 17 years)
NOAA Central Library U.S. Daily Weather Maps Archive (back to 1871)
**UCAR Image Archive (radar, satellite, sounding, surface, & upper air data/images/loops each day since 1996)
U of Wyoming Sounding Archive (GIF, PDF, or text format) from across North America since 1973
State College NWS Past Weather and Climate Homepage (access records, normals, climate graphs, etc.)
Historical Tropical Weather Events (organized by year for both Atlantic and Pacific since 1998)
NOAA Storm Events Database (since 1950) (records from all sorts of weather events for specific date range)
COOP Site Observation Records through NOAA
NCEP Reanalysis Data
SPC Mesoanalysis Archive, SPC Main Archives Page
Historical SPC Severe Weather Database of storm reports
Climate Centers:
High Plains Regional Climate Center (ACIS Climate Maps)
Northeast Regional Climate Center
Midwestern Regional Climate Center (CLI-MATE LOGIN)
Southeastern Regional Climate Center (Climate Perspectives Maps By Region)
Maximum wind gusts over past 5 days by state
NOAA Air Resources Labratory: HYSPLIT (track air parcels)
30-day loop of analyzed 200-hPa heights and anomalies worldwide (CPC)
Global Circulation Animations: Means and Anomalies (past 1,7,30,90,365 day loops)
Past 5 Days Satellite Images and Loops, Past 7 Days Satellite Movie
Intellicast Yesterday's Radar Loop
Archives: NEXRAD (select from NWS radars), Plymouth State