Climates — Reading Comprehension Lesson

Reading Passage

Climates

Climate is the long-term average of weather conditions for a region, typically measured over 30 years or more. While weather can change from hour to hour, climate changes only gradually over decades or centuries. Two cities at the same latitude may have very different climates: San Francisco, California, and Richmond, Virginia, are at similar latitudes, but San Francisco has mild temperatures year-round while Richmond has hot summers and cold winters. Climate is shaped by a combination of factors: latitude, elevation, proximity to oceans, ocean currents, prevailing winds, and the presence of mountain ranges.

Latitude — distance from the equator — is the most important factor determining climate. Tropical regions near the equator receive direct, intense sunlight year-round and are hot. Polar regions receive sunlight at a low angle and have long, dark winters, making them very cold. Temperate regions in between have four distinct seasons. Elevation also has a major effect: temperatures drop about 3.5°F for every 1,000 feet of elevation gain. Mount Kilimanjaro in Tanzania sits near the equator but has permanent glaciers on its summit because of its great height. This is why mountain ranges can have dramatically different climates from nearby lowlands.

Oceans moderate climate by absorbing heat in summer and releasing it in winter, reducing temperature extremes in coastal regions. Cities near large bodies of water — like San Francisco or London — have milder climates than inland cities at the same latitude. Ocean currents carry warm or cold water across vast distances, strongly influencing coastal climates. The Gulf Stream carries warm tropical water northward along the eastern United States and across the Atlantic, keeping Western Europe much warmer than it would otherwise be. The cold California Current brings cold water down the Pacific coast, creating San Francisco’s characteristic cool, foggy summers.

Scientists classify Earth’s climates into major types. The Köppen climate classification system divides climates into five main groups based on temperature and precipitation patterns: tropical (hot and wet year-round), dry (deserts and steppes), temperate (mild with distinct seasons), continental (cold winters, warm or hot summers), and polar (bitterly cold year-round). Within each group are many subtypes. Understanding climate is essential for agriculture, architecture, urban planning, and managing natural resources. Today, human activities are altering Earth’s climate by increasing concentrations of greenhouse gases, causing temperatures to rise and precipitation patterns to shift worldwide.

Printable Worksheet

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