A very warm April, 2012, and past 12 months in the U.S. and worldwide

Looks like southeast Michigan may not be alone in having the warmest spring on record. Not only did many cities, Detroit among them, have the warmest March ever, but it was the warmest March on record for the Lower 48. While April was cooler than March, it was still the third warmest April for the U.S. as a whole.

The contiguous United States had a mean temperature of 13.2°C (55.7°F) in April 2012, which was 2.0°C (3.6°F) above the 20th century average, resulting in the third warmest April since national records began in 1895.

It's not just the spring months, either. The year to date has been the warmest ever.

January-April 2012 was the warmest such period on record for the contiguous United States, with an average temperature of 45.4 degrees F, 5.4 degrees F above the long-term average. Twenty-six states, all east of the Rockies, were record warm for the four-month period, and an additional 17 states had temperatures for the period among their ten warmest.
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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 42 percent during the January-April period, over twice the average value. Extremes in warm daytime temperatures (82 percent) and warm nighttime temperatures (68 percent) covered a large area of the nation, contributing to the record high value.

The record even extends back a full 12 months.

The 12-month period (May 2011-April 2012), which includes several warm periods for the country — second hottest summer, fourth warmest winter, and warmest March — was the warmest consecutive 12-month period for the contiguous United States. Twenty-two states were record warm for the 12-month period, and an additional 19 states were top ten warm. The 12-month running average temperature for the contiguous U.S. was 55.7 degrees F, which is 2.8 degrees F above the 20th century average.

The global temperature picture isn't quite as extreme, but it's bad enough, as April global temperatures are fifth warmest.

The globally-averaged temperature for April marked the fifth warmest April since record keeping began in 1880. April 2012 also marked the largest departure from the 20th century average temperature in more than a year.

La Niña, typically associated with cooler global temperatures, dissipated and transitioned to neutral conditions during April as sea surface temperatures continued to warm across the equatorial Pacific Ocean. According to NOAA's Climate Prediction Center, neutral conditions are expected to continue through the Northern Hemisphere's summer.


Global temperature highlights: April

• The combined average temperature over global land and ocean surfaces for April was 57.87°F (14.35°C), 1.17°F (0.65°C) above the 20th century average of 56.7°F (13.7°C). The margin of error associated with this temperature is ±0.14°F (0.08°C).
• The global temperature departure from the 20th century average and monthly rank were the highest since November 2010, near the onset of first of the back-to-back La Niñas in 2010.
• Driven by very warm land-surface temperatures, April 2012 was the warmest April on record for the Northern Hemisphere.
• This was the 36th consecutive April and 326th consecutive month with a global temperature above the 20th century average. The last April with below average temperature was April 1976. The last month with a below-average temperature was February 1985.
• The global land surface temperature was 2.5°F (1.39°C) above the 20th century average of 46.5°F (8.1°C), making it second warmest April, behind 2007. The margin of error is ±0.20°F (0.11°C). Warmer than average conditions engulfed much of the world.s land areas with the most notable warmth across Alaska, the contiguous United States, Mexico and most of Russia. Cooler than average conditions were present across northern Australia and parts of western Europe.
• Norway and Sweden experienced their coolest April since 1998.
• The United Kingdom experienced below-average temperatures, which resulted in the coolest April since 1989.
• The contiguous United States had its third warmest April since national records began in 1895.
• For the ocean, the April global sea surface temperature was 0.68°F (0.38°C) above the 20th century average of 60.9°F (16.0°C), ranking it 11th warmest. The margin of error is ±0.07°F (0.04°C). This was the 427th consecutive month with ocean temperatures above the 20th century average.

Global temperature highlights: Year to date

• For January through April, the combined global land and ocean average surface temperature was 0.83°F (0.46°C) above the 20th century average of 54.8°F (12.6°C), marking the 15th warmest such period on record, although coolest since 2008. The margin of error is ±0.16°F (0.09°C).
• The January-April worldwide land surface temperature was 1.35°F (0.75°C) above the 20th century average of 40.5°F (4.8°C), tying with 2011 as 17th warmest such period on record and coolest January.April since 1997. The margin of error is ±0.40°F (0.22°C). The global ocean surface temperature for the year to date was 0.63°F (0.35°C) above the 20th century average of 60.7°F (15.9°C) and tied with 1999 as 13th warmest such period on record and the coolest since 2008. The margin of error is ±0.07°F (0.04°°C).

After a year of wild weather in Detroit and the nation, I declared that I wouldn't be surprised by anything that came along. So far this year, I haven't been disappointed.