As autumn approaches, many wonder when cooler conditions will arrive in the US and if snowflakes will fall before Halloween. AccuWeather’s annual fall forecast, compiled by meteorologist Paul Pastelok and his team of long-range forecasters, reveals that El Niño will be a driving factor behind the weather patterns across the US this autumn. While summery weather will linger into the start of autumn for the Northeast and Midwest, there will be a “big transition” in the weather around the end of September across the Midwest and Northeast, bringing chillier air and thunderstorms. This change in pattern could also bring an early frost to parts of the Midwest by early October. The central US and Rocky Mountains are in for a major shakeup following a mild start to autumn, with temperatures across the region projected to be lower than last October. Wildfires are also expected to be a risk in Northern California, eastern Oregon, eastern Washington, Idaho, and parts of Nevada, with more Santa Ana wind events in October than last year. https://www.accuweather.com/en/weather-forecasts/accuweathers-2023-us-fall-forecast/1562599