The January-June period was the warmest first half of any year on record for the contiguous United States. The national temperature of 52.9°F was 4.5°F above average. Most of the contiguous U.S. was record and near-record warm for the six-month period, except the Pacific Northwest. Twenty-eight states east of the Rockies were RECORD WARM (including Nebraska) an additional 15 states were top ten warm.
The U.S. Climate Extremes Index (USCEI), an index that tracks the highest and lowest 10 percent of extremes in temperature, precipitation, drought and tropical cyclones across the contiguous U.S., was a record-large 44 percent during the January-June period, over twice the average value. Extremes in warm daytime temperatures (83 percent) and warm nighttime temperatures (70 percent) covered large areas of the nation, contributing to the record high value.