1. Climatological Context and Frequency

Hail Prone Region

• Cheyenne is situated in the U.S. “Hail Alley”, one of the highest hail-frequency regions in North America due to the interaction of Plains moisture and upslope flow from nearby terrain. National Weather Service+1
• Historical studies indicate eight to nine hailstorms per year on average, making Cheyenne among the most hail-prone cities in the country. NOAA Institutional Repository

Typical Season and Daily Patterns

• Hail in the Cheyenne area is most common late spring through midsummer, with June being the peak month followed by July. National Weather Service
• Hail can start as early as March and extend into October, but the highest likelihood of severe hail (≥1 inch) occurs from May through early September. National Weather Service
• The typical time of day for hail reports is late afternoon to early evening, especially near 4:00 PM local time. National Weather Service

Report Statistics (2000–2023)

• Since 2000, National Weather Service data show variations year-to-year in hail reports around Cheyenne.
• 2010 and 2019 had particularly high numbers of hail reports.
• 2023 was notable for high counts of significant hail (≥2 inches).
• On average, 6+ hail days per year occur near Cheyenne for hail ≥1 inch. National Weather Service

2. Historical Hail Reports and Notable Storms

Early Records (1890s–1990s)

• An in-depth NOAA historical memoranda document hailstorms affecting Cheyenne between 1892 and 1996, showing that hailstorms have long been a part of the local climate. NOAA Institutional Repository

Major 20th-Century Hail Events

• August 1, 1985: One of Cheyenne’s most catastrophic storms included exceptional hail up to 2 inches in diameter, with hail accumulating in feet-deep drifts amidst flooding conditions. WyoHistory+1
• This event caused substantial damage and high insured losses, and remains a defining severe weather event for the city.
• Other historically significant hail events in Wyoming with large loss costs occurred near Cheyenne in 1979 and 1987, making Cheyenne the location of three of the top five hail loss events in the state through at least the mid-1990s. wrds.uwyo.edu+1

21st-Century Severe Storms

• July 29, 2016: A severe hailstorm with golf-ball to baseball-size hail struck Cheyenne, causing property damage and minor injuries. National Weather Service
• August 2019: Multiple rounds of hail-producing thunderstorms impacted eastern Wyoming and nearby Nebraska, with reports of broken windows and vehicle damage. KGAB AM 650
• Recent hail reports in 2023–2025 continue to include frequent hail observations ranging from quarter-size to larger stones near Cheyenne, with severe thunderstorm warnings issued regularly during active storm periods. Interactive Hail Maps

3. Damage and Impact

Economic and Physical Impact

• Historically, hail in the Cheyenne area has caused significant property and crop damage, with the largest losses tied to major events in the mid-1980s and additional hundreds of smaller damage reports over time. wrds.uwyo.edu+1
• Hail can damage vehicles, roofs, siding, crops, and infrastructure, and lead to higher insurance claims during active storm seasons.

Safety Considerations

• Severe hailstorms can pose risks to people and animals outdoors, and large hail (>1 inch) is often associated with severe thunderstorm warnings issued by the National Weather Service. National Weather Service

4. Trends and Reporting Considerations

Changes in Reporting Criteria

• Since 2010, hail reports have been influenced by changes in National Weather Service criteria (e.g., the threshold for “severe hail” set at ≥1 inch diameter), which can affect long-term trend interpretation. National Weather Service

Population and Reporting Density

• Report data may be biased by population centers and road networks; more sparsely populated surrounding areas may experience hail without formal reports. National Weather Service

Summary

• Cheyenne, Wyoming is one of the most hail-prone cities in the United States, with frequent hailstorms, especially from late spring through summer.
• Hail events vary from frequent smaller-sized hail to occasional large and damaging hailstorms recorded in historic years (1985, 1987, 2016).
• The combination of local topography and regional climatology positions Cheyenne within a core area of hail frequency, leading to ongoing risk for hail impacts seasonally.
• Historical data extend back over a century, and systematic reporting has improved in recent decades, offering insights into both typical hail frequency and major severe hail events.