Climate Chart of Boise, USA

Climate overview

Temperature

Monthly mean temperatures are highest in July, at 27.1 °C, and lowest in January, at -0.6 °C. These are averages for the whole month, not daytime high temperatures, so they should not be read as a forecast of afternoon conditions. Across the calendar months, the unweighted mean of the monthly mean temperatures is 12.0 °C. It is a summary of monthly averages rather than a day-weighted annual average, and it does not show the range of temperatures visitors may encounter within a month.

Rain

Mean daily rainfall is highest in May, at 1.18 mm/day, and lowest in July, at 0.07 mm/day. These are daily mean amounts, not monthly totals; the lower average does not guarantee rain-free days or indicate how often rain occurs. The unweighted mean across the monthly daily-rainfall averages is 0.73 mm/day. It provides a broad reference point, but cannot describe the timing or intensity of rainfall on an individual day.

Sunshine

Mean daily sunshine reaches its highest level in July, at 13.56 hours/day, and its lowest in December, at 5.31 hours/day. These averages can help with planning outdoor time, but sunshine duration is not the same as day length and does not guarantee clear skies on a particular date. The unweighted mean across monthly sunshine averages is 9.62 hours/day per day. This summarizes the calendar-month means rather than the sunshine visitors should expect on any one day.

Snow

Mean daily snowfall is highest in December, at 5.29 mm/day; the unweighted mean across monthly daily-snowfall averages is 1.38 mm/day. These figures describe average amounts, not the number of snowy days, snow depth, snow cover, or conditions for skiing.