Sun Valley (ID) Temperature by Month

Sun Valley, Idaho, United States of America has an average annual maximum temperature of 13°C (55°F), ranging from 0°C (32°F) in December to 27°C (81°F) in July. Below you'll find a full monthly breakdown and a comparison with cities worldwide.

Depending on the time of the year, temperatures range from comfortable to very cold in Sun Valley. At night, minimum temperatures range from 8°C (46°F) in July to -12°C (10°F) in December.

The chart below illustrates the average maximum day and minimum night temperatures in Sun Valley by month:

Daily lows are most common between 4 AM and 6 AM. By 3 PM temperatures reach their daily high, driven by peak solar heating.

The chart below shows the average temperature throughout the year:

Sun Valley's average annual maximum temperature is 13°C (55°F). To put that in context, here's how it compares to a few well-known destinations:

Barcelona, Spain has an annual average of around 21°C (70°F), with warm summers and mild, fairly short winters.

Zermatt, Switzerland averages just 4°C (39°F) annually due to its altitude, with very cold winters and cool summers even at its warmest.

Boston, USA averages 16°C (61°F) annually, with four distinct seasons and cold winters that rival northern Europe.

Melbourne, Australia averages 20°C (68°F) annually, known for unpredictable weather, with four seasons sometimes happening in one day.

Climate temperature data is typically calculated as a 30-year average. This smooths out year-to-year variability and gives a more reliable picture of what a place is actually like, rather than what happened in any single unusual year.

The readings come from a range of sources, land-based weather stations, ocean buoys, ships, and satellites. That data is collected by weather services around the world, then pooled, quality-checked, and averaged to produce the climate records you see here.

Whether a city sits on the coast or deep inland makes a significant difference to its climate. Coastal areas tend to have more stable temperatures year-round, large bodies of water absorb heat slowly in summer and release it gradually in winter, keeping extremes in check. Cities far from the sea don't benefit from that buffer, which is why continental climates tend to have hotter summers and colder winters than their coastal counterparts at the same latitude.

For more on Sun Valley's weather, including monthly rainfall, sunshine hours, and humidity, visit our Sun Valley climate page.