U.S. National Overview

August 2007

• For summer 2007 (June-August), the average temperature for the continental U.S. was 73.8°F (23.2°C), which was 1.7°F (1.0°C) above the 20th century mean and the sixth warmest summer since national records began in 1895, based on preliminary data.

• This was the warmest summer for Utah and Nevada, and one of the 10 warmest summers on record for 11 other states. Only Texas and Oklahoma were cooler than average.

• While temperatures in the heavily populated Northeast were near average, the much warmer than average conditions in the Southeast and throughout the West led to above average residential energy demand for the nation. Using the Residential Energy Demand Temperature Index (REDTI - an index developed at NOAA to relate energy usage to climate), the nation's residential energy demand was approximately 8 percent higher than what would have occurred under average climate conditions for the season.

• For the contiguous United States, the average temperature for August was 75.4°F (24.1°C), which was 2.7°F (1.5°C) above the 20th century mean and the second warmest August on record, based on preliminary data.

• A severe heat wave persisted throughout much of the month across southern and central parts of the nation. More than 30 all-time high temperature records were tied or broken and more than 2000 new daily high temperature records were established.

• Raleigh-Durham, NC equaled its all-time high of 105°F (40.6°C) on August 21, and Columbia, SC had 14 days in August with temperatures over 100°F (37.8°C), which broke the record of 12 set in 1900.

• The warmest August in the 113-year record occurred in eight eastern states (West Virginia, Kentucky, Tennessee, the Carolinas, Georgia, Alabama, and Florida) along with Utah. For the Southeast, the length, severity and area of the heat wave led to comparisons with events in 1983 and 1954. The nation's August REDTI was the highest August value in 113 years and was 16 percent above the mean energy consumption for the month. Alaska was 3.28°F (1.82°C) warmer than the 1971—2000 mean in August.

• The summer was drier than average for the nation as a whole. Rainfall was below average in the Southeast, mid-Atlantic, and Ohio Valley as well as the northern Plains and Northern Rockies.

• A persistent atmospheric pattern brought much drier-than-average conditions to the Southeast and much wetter-than-average conditions to the South region. Texas had its wettest summer on record and Oklahoma its 4th wettest. In the Southeast, this was the driest summer since records began in 1895 for North Carolina and the second driest for Tennessee.

• A hot and dry July in the northern Rockies contributed to a fast start to the wildfire season, and August remained very active as warmer and drier-than-average conditions persisted in many areas. By early September, more than 7 million acres had burned across the nation, most of it in the western U.S.

• The record warmth and below average rainfall of August led to an expansion of drought in the Southeast and parts of the mid-Atlantic and Ohio Valley. At the end of August drought affected approximately 83% of the Southeast region and 46% of the contiguous U.S., according to the federal U.S. Drought Monitor.

• Severe drought persisted throughout much of the West as well as an area that stretched from northern Minnesota to the Upper Peninsula of Michigan.

• Sandwiched between drought to the north and south, the central third of the Midwest received record precipitation in August as a persistent frontal system provided a focus for heavy rain and thunderstorms. Precipitation was two to three times normal for the month in a wide band across the central Midwest, where Iowa had its wettest August on record. Only 10 to 25 percent of normal precipitation amounts fell in southwestern Kentucky and less than 25 percent of normal fell in Michigan's Upper Peninsula.

• Many areas in Tennessee, Alabama, Mississippi, Arkansas, Georgia, and South Carolina had more than ten days of triple digit temperatures in August. It was, by far, the hottest month on record in Tennessee, and the average high temperature for the month was a remarkable 82.9°F (28.3°C), more than 6.6°F (3.7°C) above the monthly average and more than 2.8°F (1.6°C) above the previous record set in 1936. More information about the exceptional heat in August can be found at the special August heat wave page.
  
  
• Drought severity worsened during the month of August in the Central and Southeast regions and in parts of Montana, Idaho, and northern Wisconsin and Minnesota, the northern plains, the Midwest, and the mid-Atlantic. The most severe drought in the nation was concentrated in a large portion of Alabama, Mississippi, Kentucky, Tennessee, Georgia, Florida, the western Carolinas, and in small portions of Arkansas, Virginia, and Ohio. Extreme drought conditions also persisted or intensified in the southwestern states of Arizona, California and Nevada, as well as in Idaho, Montana, Wyoming, South Dakota, Nebraska, Minnesota, Wisconsin, and the Upper Peninsula of Michigan. For more information on drought during August, please visit the U.S. Drought Watch page.
  
  
• In the tropical Pacific Ocean, La Niña conditions were developing. By the end of August, sea-surface temperature (SST) anomalies remained positive in the western equatorial Pacific and became more negative in the eastern equatorial Pacific. Most dynamical models are forecasting the strengthening of the La Niña conditions in the next couple of months, while some statistical models are forecasting the return of El Niño Southern Oscillation (ENSO)-neutral conditions. A developing La Niña may result in wetter than normal conditions in the Pacific Northwest and drier than normal conditions in the southwestern U.S. in the fall. For additional information on ENSO conditions, please visit the NCDC ENSO Monitoring page and the latest NOAA ENSO Advisory.

• August Temperature: 2nd warmest August in the 1895—2007 record.  The preliminary nationally-averaged temperature was 75.45°F (24.14°C), which was 2.67°F (1.48°C) above the 1901—2000 (20th century) mean.
  
  
• August Precipitation: 37th driest nationally in the 1895—2007 record. An average of 2.44 inches (62.0 mm) fell over the contiguous U.S. in August, which was 0.16 inches (4.0 mm) below the 20th century mean for the month.
  
  
• June—August Temperature (3-Month): 6th warmest in the 1895-to-present record, 1.72°F (0.96°C) above the 20th century mean. The preliminary nationally-averaged June—August temperature was 73.84°F (23.24°C).
  
  
• June—August Precipitation (3-month): An average total of 7.93 inches (201.4 mm) of precipitation fell during this 3-month period, which corresponds to a ranking of 32nd driest over the 1895—2007 period and is 0.32 inches (8.1 mm) below the 20th century summer mean.
  
  
• March—August (6-month): The national average temperature was the 3rd warmest for this 6-month period. The preliminary nationally-averaged temperature was 64.05°F (17.81°C), which was 2.05°F (1.14°C) above the 20th century mean. At 15.40 inches (391.2 mm), the March—August precipitation was below average and ranked as the 37th driest such period in the 1895—2007 record with 0.6 inches (14.1 mm) below the mean.
  
  
• January—August (Year-to-date): The 13th warmest January—August on record. The preliminary nationally-averaged year-to-date temperature was 56.08°F (13.38°C), or 1.39°F (0.77°C) above the mean. The year-to-date period was the 30th driest January—August in the 113-year record, receiving a national average of 19.26 inches (489.2 mm) of precipitation during the period, or 0.94 inches (23.8 mm) below the 20th century mean.
  
  
• September 2006—August 2007: This was the 13th warmest such period in the 1895—2007 record.  The preliminary nationally-averaged annual temperature was 53.91°F (12.17°C), which was 1.09°F (0.61°C) above the mean. Precipitation for the September 2006—August 2007 period ranked as the 46th wettest September to August in the 112-year record.  The nationally-averaged annual precipitation accumulation was 29.81 inches (757.2 mm), ranking 0.66 inches (16.9 mm) above the 20th century mean.

• Alaska had its 3rd warmest August since records began in 1918, with a temperature 3.28°F (1.82°C) above the 1971—2000 average.
  
  
• Alaska had its 4th warmest June—August on record, with a temperature 1.91°F (1.06°C) below the 1971—2000 average.
  
  
• Alaska had its 28th warmest January—August on record, with a temperature 0.36°F (0.2°C) above the 1971—2000 average.

• The average August temperatures set new records in eight central and southeastern states: Alabama, Florida, and Georgia, Kentucky, North Carolina, South Carolina, Tennessee, West Virginia, and in Utah. Iowa had the wettest August on record and Nebraska had its 4th wettest August since 1895. Relatively little precipitation during the month resulted in the 2nd driest August in North Carolina, Rhode Island, and Tennessee.
  
  
• June—August temperatures across Nevada and Utah set a new record high average temperature for this period. Texas had its 15th coolest three month June—August on record. Texas set a new record for the most precipitation with 13.19 inches (335.0 mm) from June—August. On the dry side, North Carolina had the driest June—August period and Tennessee had the 2nd driest June—August period on record.
  
  
• Temperatures over the past 6 months (March—August) were much above average in every region but the Northeast, South, and Southeast. A lack of precipitation ranked the period the 2nd driest in the Southeast, sixth driest in the West, and eighth driest in the Central U.S. An abundance of precipitation in the South made this the sixth wettest March—August on record.
  
  
• March—August (6-month) temperatures were much above average for 21 states and set new records in Utah and Wyoming. Idaho, Montana, Nevada, and Tennessee had the second warmest March—August on record. No states had temperatures much below normal for this period. Both Tennessee and North Carolina had the driest March to August period on record. In contrast, Texas experienced its wettest such period on record.
  
  
• So far during 2007, temperatures have been much above average for seven states, including Idaho and Utah. It was the 23rd coolest January—August on record in Texas. Alabama, Florida, North Carolina, and Tennessee had the driest such period on record. In contrast, Texas experienced its wettest January through August on record.
  
  
• Overall, the January—August precipitation across the Southeast was the driest on record. It was the 8th driest in the West region, and 9th wettest in the South region.
  
  
• Average temperatures over the past twelve months from September 2006—August 2007 were near average to much warmer than average for the Lower 48 States. Six states, including Idaho, experienced average temperatures much above normal. Only Texas experienced temperatures below normal during this period. The West North Central region experienced temperatures much above normal. Precipitation during this period varied sharply from one region to another. The West experienced its second-driest September—August period, and the Southeast experienced its fourth-driest. Florida was record driest during the most recent September—August period, and both Nevada and Tennessee were second driest in the same period.