Fall officially arrives Friday afternoon across the United States, and depending on where you are, it may still feel like summer.

The summer heat is expected to linger everywhere east of the Rocky Mountains where some temperatures may rival those of the hottest parts of the year.

Cooler fall weather will arrive in full force west of the mountains as a more fall-like pattern begins to settle in.

That cooler air will take roughly a week to trek across the U.S. because the final week of September and the first days of October are likely to be cooler than average for the mid-sections of the country according to the latest long-term forecast models.

This means late September and early October may be another chance to break out the cozy sweaters and other fall apparel, but don't ditch your summer clothes completely.

The latest outlook for October is hinting at warmer weather making a comeback in the western half of the United States as well as most of the Northeast and parts of the Upper Midwest.

Regardless of the temperature, the days continue to get shorter, and that triggers leaves changing colors. You can find out where the prime fall foliage is with this map.

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