The average temperature for the contiguous U.S. during 2013 was 52.4°F, 0.3°F above the 20th century average, tying with 1980 as the 37th warmest year in the 119-year period of record. The year consisted of a warmer-than-average winter, summer, and autumn, and a cooler-than-average spring.
For the year, the average precipitation total for the contiguous U.S. was 31.17 inches, 2.03 inches above the 20th century average. This marked the 21st wettest year on record and the wettest since 2009. California was record dry, while Michigan and North Dakota were record wet; Alaska had its third wettest year.
Here are some notes summarized from the report.
- There 7 weather and climate disaster events of more than $1 billion each in 2013.
- Drought conditions improved in the SE and central U.S., but worsened in the Far West.
- Tornado count of 900 was low relative to 1,250 avg. May did have some EF5 storms.
- The 13 tropical storms in the north Atlantic was a little above avg. Only 2 formed hurricanes.
- No contiguous states reported annual temperatures in their 10 hottest or coldest.
- Alaska had its 10th warmest year in 95 yrs of record keeping.
- Top 10 cool spring in 12 states from northern plains to SE. Top 10 warm spring in CA and AZ.
- Top 10 warm summer in 8 western states. Below avg summer in midwest and SE.
- Cold December in the east and warm in the west.
In terms of year-long precipitation, each state ranked it on a scale of 1-the lowest to 119-the highest. This map shows the results. California and Oregon reported 1 and 4 for the driest. North Dakota and Michigan reported 119 with several SE states close behind.
The National Climatic Data Center also published the North American Drought Monitor Indices. There are 9 national maps showing the % of normal precipitation when compared to the 50 year average during the base period 1951-2001. For example, there is a map showing the recent 60 month average precipitation compared to the 50 yr avg. There are also maps for the recent 48, 36, 24, 12, 6, 3, 2, and 1 months. Comparing the maps is difficult, requiring scrolling. I placed the maps into a movie format with each frame showing for several seconds before changing to the next map. In this format, the user can stop, start, rewind, the movie and more easily see the trends for any part of the country.
The focus in this movie is on the relief of drought in the mid-west and southeast, with intensified drought in the far west.
For California in particular, this chart illustrates their problem. The blue line is the normal precipitation pattern. It rises to 3-4″ values during the winter months and falls to less than 1″ in the summer. The red bars indicate precipitation has been below normal values. That has been true each of the recent three winters.