This is When Hurricane Season Starts and Ends

Be prepared by learning key hurricane season dates and peak times, and plan accordingly. 

By Deirdre Mundorf | Published Aug 30, 2021 12:22 PM

when is hurricane season

When does hurricane season start? When does hurricane season end? These are two very common questions for those who want to be prepared in the event a hurricane strikes. While many who live in areas commonly struck by hurricanes are probably all too familiar with the start and end of the season, others who are planning to move to or travel to hurricane-prone locales aren’t as well acquainted with NOAA weather trends and the ins and outs of hurricanes. So, are hurricanes a concern right now? When does hurricane season end? Let’s dive in and explore these questions.

Related: Be Prepared for Natural Disasters

What is a hurricane?

A hurricane is a tropical cyclone, which is a type of storm that forms over subtropical or tropical waters. The wind speeds of a tropical cyclone determine whether it is considered a hurricane, a tropical storm, or a tropical depression. In order for a tropical cyclone to be called a hurricane, it must have sustained wind speeds of at least 74 miles per hour. Storms with sustained wind speeds between 39 and 73 miles per hour are called tropical storms, while those with sustained wind speeds less than 39 miles per hour are referred to as tropical depressions.

Tropical cyclones with wind speeds greater than 73 miles per hour are further classified into five categories based on the following ranges.

  • Category 1 Hurricanes: sustained winds of 74 to 95 mph
  • Category 2 Hurricanes: sustained winds of 96 to 110 mph
  • Category 3 Hurricanes: sustained winds of 111 to 129 mph
  • Category 4 Hurricanes: sustained winds of 130 to 156 mph
  • Category 5 Hurricanes: sustained winds of 157 mph or more
when is hurricane season

What are the key conditions required for a hurricane to form? 

Three key conditions must be present in order for a hurricane to form: heat, water, and low wind shear. Hurricanes originate in the region just above the equator. The warm air over the ocean rises, and new cooler air takes its place. This creates an area of low pressure. As this process continues, swirls of air begin to form. And, because the warm air cools down as it rises, it condenses, creating clouds. The process continues to repeat itself, generating a growing and spinning system.

Low wind shear is also a key requirement for a hurricane. Wind shear is a change in wind speed and/or direction over a relatively short distance in higher areas of the atmosphere.
Where strong wind shear is present, hurricanes cannot form or strengthen. When wind shear levels are low, however, as can be the case over warmer tropical waters, a hurricane will be able to continue forming and strengthening.

Because of Earth’s rotation, tropical cyclones that form in the Northern Hemisphere rotate counterclockwise, while those in the Southern Hemisphere rotate clockwise. North of the equator these storms are called hurricanes, and south of the equator they’re known as cyclones.

Related: Hurricane Season: 10 Myths Not to Believe

Atlantic hurricane season spans June through November.

The official dates for the Atlantic hurricane season are June 1 through Nov. 30, although it is possible for hurricanes to form outside of this range. While this is rare, hurricanes in the Atlantic have been reported as early as January and as late as December.

Working from historical averages, the Weather Channel identified July 27 as the average date of the first Atlantic hurricane. Keep in mind, though, that this is simply an average; the first hurricane can form before or after this date.

Atlantic hurricanes may form in waters anywhere between the central Atlantic Ocean and the Gulf of Mexico. This means that they impact many different areas surrounding the Atlantic Ocean or Gulf of Mexico, including the Caribbean, Central America, the East Coast of the United States, the Gulf Coast of the United States, and eastern Canada.

when is hurricane season

Eastern Pacific hurricane season runs from May through November.

When is hurricane season over in the eastern Pacific and when does it start? Hurricane season in the eastern Pacific starts in May, a few weeks earlier than Atlantic hurricane season. The official start of the eastern Pacific hurricane season is May 15, and the season doesn’t end until Nov. 30. As with the Atlantic hurricane season, it is possible for hurricanes to form outside of these dates.

Most eastern Pacific hurricanes form off the coast of central Mexico, where the water is warm. However, between the easterly winds and the colder water temperatures found in the Pacific Ocean near the coast, Pacific hurricanes tend to head toward Asia instead of the West Coast of the United States.

Peak hurricane season for both U.S. coasts is between August and October.

While hurricane season starts in May or June and doesn’t officially end until the last day of November, hurricanes in the Atlantic and Pacific are most likely to form between August and October. In most years, 90 percent of hurricanes will form during these three months, with Sept. 10 representing the statistical peak of the season.

While the period between August and October represents the peak of hurricane season, this does not mean that hurricanes that occur outside of these months will be milder or less severe. Strong storms can develop at any point during hurricane season, so you should always be prepared.

Related: How to Survive a Hurricane: 21 Smart Preps You Can Make Now

when is hurricane season

The best hurricane preparation is education.

Whether you live in a hurricane-prone region or are planning on moving to or visiting such an area, it is important to develop an understanding of what hurricanes are, the dates of hurricane season, and relevant terminology. Increasing your understanding of these topics will help you make preparations and decisions that will keep you and your loved ones safe from the destruction that hurricanes leave in their path.

Keep yourself up to date with the NOAA forecasts and predictions for your area, and always heed the advice of meteorologists and local officials regarding warnings and evacuations. Start making a plan now, and take steps to prepare for hurricane season.