(COLORADO) – We are now entering the peak of the tropical season. While Colorado does not experience hurricanes directly, it is important to understand how they form and why this time of year is so active for other parts of the United States and the country. 

Hurricane season begins in early summer and stretches into late fall, even extending into the start of winter. However, the busiest time of year occurs in September, which is when the highest number of tropical systems, including major hurricanes, typically develop.

So why is September the peak? The answer comes down to the ingredients needed for hurricanes to form.

The most important factor is warm sea-surface temperatures. Throughout the summer, the ocean absorbs heat, and by September and October, it has reached its warmest levels. This stored heat helps fuel tropical systems and keep the tropics alive, even as the air is cooling off inland.

Other key ingredients include low wind shear and abundant moisture, not only at the ocean’s surface but also higher in the atmosphere. This moisture keeps storms energized as they grow.

Another critical factor is location. Hurricanes need to form at least five degrees away from the equator to benefit from the Coriolis effect, which creates the spin needed for tropical systems from the rotation of the Earth. This is why hurricanes cannot cross the equator.

Additional conditions that can help storms form include the absence of dry air, which can weaken or disrupt systems, unstable atmospheric conditions, low-level convergence where surface winds collide, and the presence of an existing disturbance to get development started.

While the process is complex, these basic ingredients highlight why the peak of the season is happening now. As the weeks continue, more tropical systems are likely to make headlines, and understanding the science behind them helps explain why.