Cool weather barely outweighed the warm in the lower 48 in July, which ended just a fraction of a degree below normal in a month that was anything but average. Two extremes ruled the month — record cool in the eastern and central U.S., and record warmth in the West, where California appears to be continuing its path to warmest year on record.
Across the contiguous U.S. as a whole, July wound up at 0.3 degrees below the 20th century average which makes it the coolest July since 2009, according to the National Climatic Data Center. Thirteen states in the central U.S. saw a top 10 coolest July on record last month. Both Indiana and Arkansas saw their coolest July on record. The number of cool records were double the warm records during the month — 5,508 record cool temperatures were set, and 3,333 of those were cool daytime temperatures.
But “cool” was only half the story.
Six western states saw one of their top 10 warmest Julys, and California continued its warmest year-to-date on record during a historical drought.
California’s average temperature from January through July was 60.9 degrees — 4.6 degrees above the 20th century average. This beat the previous year-to-date record by an astonishing 1.4 degrees. It might not seem like much, but on multiple month time scales, fractions of a degree can make all the difference in record-setting, and California is going off the charts.
Prior to this record, California’s warmest January to July period was in 1934, when the average temperature was 59.5 degrees. 1934 also holds the record for warmest calendar year overall, though 2014 appears determined to beat it.
The combination of heat and scorched earth are playing a mean game on the state, creating a positive feedback loop of intense, hot, dry weather. The hot sun beats down, baking the moisture out of the earth, and as the earth dries, it increases the temperature near the ground, which evaporates even more moisture. If there’s any left.
The area of California in exceptional drought — the worst drought category — increased by 22 percent in the month of July alone. Nearly 60 percent of California is now in exceptional drought, according to the U.S. Drought Monitor.