a. Overview

This chapter provides summaries of the 2017 temperature and precipitation conditions across seven broad regions: North America, Central America and the Caribbean, South America, Africa, Europe, Asia, and Oceania. In most cases, summaries of notable weather events are also included. Local scientists provided the annual summary for their respective regions and, unless otherwise noted, the source of the data used is typically the agency affiliated with the authors. Please note that different nations, even within the same section, may use unique periods to define their normals. Section introductions will typically define the prevailing practices for that section, and exceptions will be noted within the text. In a similar way, many contributing authors use languages other than English as their primary professional language. To minimize additional loss of fidelity through reinterpretation after translation, editors have been conservative and careful to preserve the voice of the author. In some cases, this may result in abrupt transitions in style from section to section.

b. North America

This section is divided into three subsections: Canada, the United States, and Mexico. All anomalies are with respect to the 1981-2010 base period, unless otherwise noted.

Much of North America had warmer-than-average conditions during 2017. The annual temperatures for each country were among the 10 warmest years for their respective records, with Mexico having its warmest year on record. Precipitation varied greatly across the continent, with the United States and Mexico recording near-average national precipitation totals. Annual precipitation across Canada was mostly near to below average, with only parts of the east experiencing above-average conditions. Warm, dry conditions across the west contributed to the development of one of the earliest and largest fires ever recorded in Canada. Over the course of the year, the U.S. experienced 16 weather and climate events that each caused over $1 billion (U.S. dollars), tying with 2011 as the highest number since records began in 1980.

1) CANADA--L. A. Vincent, R. Whitewood, D. Phillips, and V. Isaac

In Canada, 2017 was characterized by higher-than-average winter mean temperatures from the Yukon to Atlantic Canada, followed by spring, summer, and autumn mean temperatures near or below average across the country. Precipitation measured at 28 available stations indicates wetter-than-average spring conditions across the country and drier-than-average summer conditions mainly in southern British Columbia.

(i) Temperature

The annual average temperature in 2017 for Canada was 0.7[degrees]C above the 1981-2010 national average, its tenth warmest year since nationwide records began in 1948 (Fig. 7.1). Four of the ten warmest years have occurred during the last decade, with 2010 being the record warmest (+2.2[degrees]C). The national annual average temperature has increased by 1.8[degrees]C over the past 70 years. Spatially, annual departures above +2.0[degrees]C were recorded in the north (Fig. 7.2a), which resulted in two provinces/territories reporting annual average temperatures among their ten highest: Northwest Territories (fifth highest) and Nunavut (seventh highest).

Seasonally, winter (December-February) 2016/17 was 1.8[degrees]C above average--the seventh warmest winter on record. The national winter average temperature has increased by 3.4[degrees]C over the past 70...