WX Blog: Why is June 1st so important to Meteorologists?


June 1st’s come and go every year, for most of the world the day doesn’t have much significance. That is unless you celebrate National Olive Day, or are a big fan of Western Australia which is also celebrated on June 1st. But for most of the world, June 1st is just another day. Except if you’re a Meteorologist.

In the world of Meteorology June 1st commemorates two significant dates, the beginning of Hurricane Season in the Atlantic Basin, and the beginning of Meteorological Summer. Both of these events signify an element of change in the weather as a whole. Hurricane season means more activity in the tropics, and Meteorological Summer means things are starting to heat up across the country. Let’s take a closer look into each and talk a little bit more about their significance.


Hurricane Season runs from June 1st to November 30th, every year. These dates while seemingly innocuous encompass 97% of all tropical activity in the Atlantic Basin every year based on climatology. What about the other 3% of tropical activity, why doesn’t it cover that you may ask? To put it simply that 3% can be quite erratic on when it actually occurs. Since records have been kept there has been at least one tropical or sub-tropical storm in every calendar month. Yes, even January. Speaking of out of season storms, 2020 marked 6 consecutive years with named storms forming outside of Hurricane Season.

The forecast for the 2020 Hurricane Season from NOAA’s (National Oceanic and Atmospheric Administration) Climate Prediction Center, a division of the National Weather Service (NWS) is for above average tropical activity. But first what is average for the Atlantic basin?

Image Courtesy: NOAA/NHC
  • 11.3 named storms total. This encompasses every storm of Tropical Storm (39 mph or more) strength or greater
  • 6.2 Hurricanes. This is every storm that was Category 1 (74 mph or more) strength or greater
  • 2.3 Major Hurricanes. This is every storm that was Category 3 (111 mph or more) strength or greater
A summary infographic showing hurricane season probability and numbers of named storms predicted from NOAA's 2020 Atlantic Hurricane Season Outlook.
Image Courtesy: NOAA/NHC

This years forecast shows a 60% chance of being above normal, with 13-19 named storms, 6-10 Hurricanes, and 3-6 Major Hurricanes. It’s important to remember when viewing the graphic below and the information listed in this paragraph that this is a forecast, not a given. For more information regarding how this forecast was developed you can see the original forecast here.


Many of you know your standard seasons, Spring, Summer, Fall and Winter. These are defined by the Earths axial tilt and it’s orbit around the sun. When they begin will vary each year in both time of day and the date itself due to changes in the eccentricity of earths elliptical orbit. But the changing of the seasons generally fall within the 19th to the 23rd of the months March, June, September and December (Spring, Summer, Fall and Winter). Outside of the astronomical seasons, as they’re referred to, there is another set of seasons, Meteorological Seasons. These operate on a more rigid schedule influenced more by trends in temperatures and weather patterns versus earths position around the sun. They’re as follows

  • March 1st to May 30th: Meteorological Spring
  • June 1st to August 30th: Meteorological Summer
  • September 1st to November 30th: Meteorological Fall
  • December 1st to February 28th (or 29th if it’s a Leap Year): Meteorological Winter

June 1st marks the beginning of Meteorological Summer, every year. This system helps Meteorologists to manage data more efficiently, and well it makes more sense than the astronomical seasons sometimes. Often times it feels like summer in early June but you can’t really call it summer yet since Summer doesn’t officially begin until we reach the Summer Solstice near the end of June. Well now you know a loop hole to be able to say it’s summer, before it really is! Just make sure you call it Meteorological Summer first!

Edit: A previous version of this article stated “Named Storms” included Tropical Depressions this has been updated to the correct term of Tropical Storms

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