Published: 2008-10-22 10:24:12
Updated: 2008-10-22 10:24:12
Posted October 22, 2008
By Beth Gardner
MIKE MOSS SAYS: Beth, The National Climatic Data Center has a nice collection of comparative climatology statistics for about 300 stations around the U.S. that includes a listing of the average number of days per month and per year with measurable precipitation - this should give a reasonable answer for your first question, and can be accessed online at
I can't think of a good publicly accesible (and free) place to look for the number of nights with temperature falling below 50 (i.e. equal to or less than 49 assuming that's what you mean) degrees. However, I ran a threshold search using a subscription based climate analysis system, and for the RDU airport that number averages about 182 days per year (or about 188 days for low temperature equal to or less than 50).
You could make a rough estimate of those kinds of numbers by counting the number of days that the normal low temperature is equal to or less than whatever value you're interested in, but variations in how temperatures are statistically distributed and in the way in which "normal" values are computed will lead to some modest disparities. A good listing of "normal" highs and lows for RDU is available at