Lewiston (ID) Temperature by Month

Lewiston, Idaho, United States of America has an average annual maximum temperature of 19°C (66°F), ranging from 5°C (41°F) in December to 34°C (93°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 very warm to cold in Lewiston. At night, minimum temperatures range from 16°C (61°F) in July to -1°C (30°F) in December.

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

The coolest part of the day is typically between 4 AM and 6 AM, while 3 PM is usually the warmest, when solar heating is at its peak.

The chart below shows the average temperature throughout the year:

Lewiston's average annual maximum temperature is 19°C (66°F). To put that in context, here's how it compares to a few well-known destinations:

Athens, Greece sits at 23°C (73°F) on average, with hot dry summers and mild winters characteristic of the Mediterranean.

Toronto, Canada averages 13°C (55°F) annually, with cold snowy winters balanced by genuinely warm summers.

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

Brisbane, Australia averages 26°C (79°F) a year, with warm winters and hot, humid summers.

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.

Seasonal temperature shifts influence more than just how warm it feels, they also drive changes in rainfall, cloud cover, and wind patterns throughout the year.

Warmer air holds more moisture, which tends to mean heavier or more frequent rain during the warmer months. When temperatures drop in winter, any precipitation that does fall is more likely to come as snow or sleet, though in Lewiston this rarely lasts long on the ground.

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