July Weather: The 5 Things We Watch For | Weather.com (2024)

J​uly weather brings to mind sweltering temperatures since it's midsummer, but hurricane season is also beginning its upward swing and thunderstorms can be problematic in many parts of the country.

Here are five things we typically see during the month:

1. The Hottest Time Of Year For Many

July is the hottest month on average for an expansive part of the United States from the Great Basin to the Central Rockies, Central Plains, Midwest and East.

The sun is highest in the sky and delivers its most direct solar radiation over the Northern Hemisphere at the summer solstice in late June, but it takes days or weeks to warm up Earth's surface and then the air above it. That means there's a lag between the solstice and the hottest day of the year.

Highs in July are typically in the 80s and 90s for much of the contiguous U.S., with 70s in some locations closer to the Canadian border, along the Northwest coast and in the Rockies. Average highs in the 100s are typical in portions of the Desert Southwest in July.

2. Atlantic Hurricane Season Activity Begins To Tick Up

Hurricane season is typically still rather slow in July, but there's a slight uptick in activity and the areas of typical formation expand.

The eastern Caribbean Sea near the Lesser Antilles joins the Gulf of Mexico and waters off the East Coast as favored areas for tropical development.

J​uly has accounted for about 7% of the hurricane season's tropical storms since 1851, which means roughly one named storm forms in the month each year. Hurricanes are more rare, with about one of those forming every three years.

L​ast July, Hurricane Don took a long, winding, six-shaped track in the North Atlantic Ocean.

3. Severe Thunderstorm Threat Peaks In The Northeast

The jet stream migrates to the northern tier of the U.S. by July and is weaker than what we usually see in winter and spring. But because hot, humid air is so abundant in summer, it's easier for thunderstorms to form when even weaker disturbances ripple through the jet stream.

The Northeast averages the greatest number of severe thunderstorm reports in July, according to a study by NOAA's Storm Prediction Center. This includes areas around Boston, New York City, Philadelphia and Washington, D.C. This severe weather peak also holds true in parts of the Great Lakes, Northern Plains and northern Rockies.

Severe thunderstorms often take the form of squall lines with damaging, straight-line wind gusts in summer instead of the tornadoes that dominate the spring. The number of tornadoes in the U.S. is cut almost in half from June (188) to July (101), but July is still typically the fourth most active month for tornadoes.

4. Southwest Monsoon Ramps Up

The Desert Southwest monsoon usually switches into its wet phase by July.

When a dome of high pressure aloft builds over the southern Rockies or adjacent Plains, moisture flows northward from the Gulf of California, the Eastern Pacific Ocean and westward from the Gulf of Mexico. This kicks off what can be a daily ritual of mainly afternoon and evening thunderstorms over the higher terrain over the Southwest.

Near the beginning of the monsoon's wet phase in July, when moisture isn't as plentiful, these thunderstorms may produce more wind than rain, whipping up an intense dust storm known as a haboob.

Heavy rain and flooding occur in the desert more often later in summer, particularly when moisture from a remnant of an Eastern Pacific tropical system flows into the region. Increased humidity at times can take away the common "dry heat" cliché.

T​he monsoon also fluctuates in how active it is from year to year. F​or example, 2020 was the driest monsoon on record for much of the Southwest. That was followed by one of the wettest monsoons in 2021.​

5. Thunderstorm Clusters Are Common

Any national radar loop on a July morning will probably show at least one cluster of thunderstorms known as mesoscale convective systems.

Their appearance in satellite imagery is particularly dramatic, often resembling a sunny-side-up egg covering parts of one or more states.

A 2019 study found July is one of two peak months for these batches of thunderstorms, which often rumble through the Plains and Midwest.

When these clusters of thunderstorms are fast-moving, they can produce widespread damaging winds known as a derecho. If they stall, flooding rainfall is often the result. Either way, they're usually prolific lightning producers, sometimes at a rate of several thousand strikes per hour.