Idaho local data guide

Boise, Idaho Weather in July

July in Boise is historically the warmest and driest month of the year, characterized by hot, sunny afternoons and cool, comfortable evenings. While long-term climate normals indicate average high temperatures in the low 90s°F, residents should monitor local forecasts for heat advisories, as daily temperatures can frequently exceed 100°F during mid-summer.

Updated with grounded research as of 2026-07-21.

The short answer

July represents the peak of summer in Boise, Idaho, defined by consistently hot temperatures and very low precipitation. According to the 1991-2020 climate normals recorded at the Boise Airport, the region experiences an average daily high of approximately 93°F and an average low of 60°F. The city's semi-arid climate ensures low humidity levels, which often allows for significant cooling after sunset, though residents should remain prepared for occasional heatwaves common to the high desert environment.

Key facts

Average High Temperature
93°F (34°C)
Average Low Temperature
60°F (16°C)
Average Precipitation
0.21 inches

Temperature Dynamics

Boise experiences a high-desert climate, which results in substantial temperature swings between day and night. While average highs sit in the low 90s°F, it is not uncommon for temperatures to reach or exceed 100°F. The low moisture content in the air facilitates rapid cooling once the sun sets, typically providing residents with comfortable evening temperatures.

Precipitation and Humidity

Precipitation is minimal in July, contributing to the area's arid landscape. Most rainfall is sporadic and associated with isolated thunderstorm activity. Low relative humidity is a defining feature of the Boise summer, which makes the heat feel less stifling compared to more humid climates, though it also increases the risk of dehydration and requires diligent sun protection.

Planning for Outdoor Activities

For those relocating or planning local activities, the best time for outdoor exercise or recreation is during the early morning hours, typically before 10:00 AM. Evenings after 8:00 PM also offer relief as temperatures drop. Residents should check real-time NWS updates for wildfire smoke advisories, as dry July conditions in the surrounding foothills can sometimes impact regional air quality.

Common questions

Is it humid in Boise during July?

No, Boise experiences very low humidity throughout July due to its semi-arid climate, which makes the heat more manageable but increases the importance of staying hydrated.

What is the best time of day for outdoor activities?

The most comfortable time for outdoor activity is in the early morning hours or later in the evening when temperatures drop significantly from the afternoon highs.

Should I be concerned about rainfall in July?

Rainfall is rare in July, with long-term monthly averages of approximately 0.21 inches. Significant precipitation events are unusual during this time.

Related Idaho questions

  • What are the typical summer wildfire risks in the Boise foothills?
  • How does the Boise climate compare to other Idaho cities?
  • What are the best times of day for outdoor activities in Boise during July?

Sources and verification