Hurricanes, Tornadoes, Heat: The Main June Weather Changes

June isn't just known for the start of hurricane season. We still have to deal with tornadoes, increasing heat and even a surprising cool spot.

1. Hurricane In June?

• Hurricane Season: Starting June 1 and lasting to November 30, eyes shift over to the oceans. While June is usually slower compared to August, September and October, the greatest chance of development is expected around the northwestern Caribbean Sea, the Gulf and just off the coast of the Southeast. It is not too surprising for impacts to occur across land near these regions, since storms often form so close to land.
• Let's Get Statistical: While June is a slower month, there is one named storm (on average) that forms every one or two years in June. Also, a hurricane forms about one in five years. Recent Junes have proven more active, with two named storms forming in five of the last six years. Continental U.S. hurricane landfalls in the month are rare, with only four since 1950 and the last one in 1986 (Bonnie). However, tropical storms have proven to be impactful numerous times.

(​MORE: June - Hurricane Season's Opening Act)

2. Greatest Tornado Threat Area Shifts

• Tornado Threat: With the increase of heat and humidity, tornadoes are actually possible across most of the lower 48 states. The area in the greatest risk of tornadoes is from the Plains into the upper Midwest and Great Lakes. Due to the northward shift of the jet stream, the Southeast actually tends to see fewer tornadoes than earlier in the season.
• Let's Get Statistical...Again: June brought an average of 186 tornadoes each year between 2004 and 2023, which is the 3rd most behind May and April. But, it's not just about tornadoes, as hail is also very frequent in the Plains. This study provides more information. We also have to consider gusty winds. Widespread wind events, called a derecho, contribute to massive amounts of destruction of trees, power lines and structures.

3. Flash Flooding And Lightning Dangers Increase

• Excess Moisture: Thunderstorms carrying heavy rainfall become commonplace in June, remaining through the rest of the summer. It is normal to see heavy rainfall rates of one inch per hour or more, which can cause flash flooding from the South to the Midwest to the Northeast. With the increase in outdoor activities, the odds of lightning strikes increase for beach activities and sporting events.
• Deeper Dive: Warmer air means it can hold more water vapor, so rainfall potentials increase for both thunderstorms and larger-scale complexes of storms in many parts of the country. We also have to take into account the jet stream slowing as it moves north, so storms tend to move slower, which also increases their rainfall potential. And we cannot rule out the possibility of flooding from storms.

(​MORE: 5 Reasons It's The Most Dangerous Time For Flash Flooding)

4. A Growing Chance Of Heat Waves

• Heat Spreads And Intensifies: Temperatures continue to rise (on average) through June, which also includes more chances of heat waves. Average highs are in the 70s and 80s for much of the Northeast and Midwest, with 80s and 90s are common for the South. And that humidity makes those temps even worse. For the West, there's quite a range. Higher elevations are in the 60s and 70s, along with the Pacific Northwest. The Desert Southwest should see highs in the 90s and 100s.
• Specifics: Average highs in the month rapidly increase from June 1 to June 30, so let's give some examples: New York City: 75 degrees June 1 → 84 degrees June 30 | Chicago: 76 degrees June 1 → 84 degrees June 30 | Dallas: 89 degrees June 1 → 94 degrees on June 30 | Denver: 78 degrees June 1 → 88 degrees June 30 | Phoenix: 100 degrees June 1 → 107 degrees on June 30

5. June's Gloomy Spot

• Surprising Coolness: Ever hear of the "June gloom"? It is when fog and low clouds settle on Coastal California in the mornings. It usually clears up by early afternoon, but if these clouds are stubborn, these cooler temperatures can remain. Especially at beaches.
• Why Does This Happen?: Known as the marine layer, this formation is driven by cold, humid air moving over the still chilly ocean waters. This is then brought onshore due to pressure differences between a high pressure off the California coast and a thermal low pressure that develops inland due to heating. This pattern causes the low clouds to form and move inland, draping like a blanket over Los Angeles and San Diego.

Rob Shackelford is a meteorologist and climate scientist at weather.com. He received his undergraduate and master’s degrees from the University of Georgia studying meteorology and experimenting with alternative hurricane forecasting tools.