Idaho local data guide
Typical Long-Term Climate Normals for Boise in July
July is typically the warmest and driest month in Boise, Idaho, characterized by hot, high-desert summer conditions. The official long-term climate normals (1991–2020) for the Boise Air Terminal reflect a consistent pattern of high daytime temperatures and significant diurnal cooling.
Updated with grounded research as of 2026-09-15.
The short answer
In July, Boise, Idaho, experiences its peak summer heat with a long-term (1991–2020) average monthly temperature of 77.1°F. Typical daily conditions involve average high temperatures near 93°F and average low temperatures near 62°F. The month is notably arid, averaging only about 0.21 inches of precipitation, making it the driest month of the year for the region.
Key facts
- Average Monthly Temperature (1991–2020)
- 77.1°F
- Average High Temperature
- 92.7°F – 93°F
- Average Low Temperature
- 61.9°F – 62°F
- Average July Precipitation
- 0.21 inches
Understanding Climate Normals
Climate normals are calculated by the National Centers for Environmental Information (NCEI) using a standardized 30-year dataset. These figures provide a baseline for what is 'normal' for a location, rather than predicting specific daily weather or accounting for year-to-year fluctuations. The current official dataset spans the years 1991 through 2020.
- Normals are not forecasts; they represent the mean climatic conditions over three decades.
- Data for these metrics are derived from the Boise Air Terminal climate station records maintained by the National Weather Service.
Temperature and Comfort
Boise’s high-desert geography results in significant temperature swings between day and night. While July afternoons are frequently hot—often reaching into the 90s—the dry climate typically allows temperatures to cool down substantially overnight. Residents and visitors should plan for intense sun exposure during the day and cooler conditions after sunset.
Precipitation Patterns
July is consistently one of the driest months in Boise. The average monthly precipitation of 0.21 inches reflects the semi-arid nature of the region, where summer rain is infrequent and typically limited to occasional, short-lived storms. This lack of moisture is a defining feature of Idaho’s southwestern summer climate.
Common questions
Is July the hottest month in Boise?
Yes, July is historically the warmest month of the year in Boise, featuring the highest average daily temperatures.
How do climate normals differ from a daily weather forecast?
Climate normals are 30-year statistical averages used to describe the expected climate for a specific time of year. They cannot predict the weather for a specific date in the future or reflect the actual conditions of any single year.
Where does this climate data come from?
The data is primarily sourced from the Boise Air Terminal (Airport) weather station, managed by the National Weather Service (NWS) and compiled by the National Centers for Environmental Information (NCEI).
Related Idaho questions
- How do Boise's current temperatures compare to historical normals?
- Where can I find daily climate data for Boise?
Sources and verification
- National Weather Service Boise Climate Summaries (weather.gov)
- NCEI U.S. Climate Normals Overview (ncei.noaa.gov)