United States heat wave threatens 200 million as temperatures near record highs

A powerful heat dome is sweeping the United States, exposing more than 200 million people to temperatures of 38‑40 °C and heat‑index values above 46 °C. Cities such as New York, Washington DC, Philadelphia and Chicago have issued extreme‑heat alerts; New York’s forecast tops 100 °F (38 °C). The heat is jeopardising Independence Day celebrations, prompting event postponements, cooling‑center openings and power‑grid safeguards that require large energy users to run emergency generators.

In Mexico, the national meteorological service warned of strong to very strong rains on 4‑6 July, especially over Jalisco and Michoacán, while a heat wave pushes maximums to 45 °C in Baja California, Sonora and Chihuahua. Simultaneously, Yucatán faces a mix of scorching temperatures around 38‑40 °C and isolated heavy showers, with civil protection urging caution over flooding and reduced visibility.

Spain’s southern coast reports a heat spell with daytime highs up to 33 °C and UV index 10, while the Canary Islands have entered a pre‑alert for temperatures exceeding 34 °C and possible calima. Japan’s rain front is expected to bring intense downpours to Kyushu, raising flash‑flood and landslide risks. Costa Rica will see intensified rain on the Caribbean side and intermittent showers elsewhere.

Collectively, these extreme temperature and precipitation events underscore a volatile early‑July climate pattern across the Americas, Europe and Asia.