Sidney (MT) Temperature by Month

The average annual maximum temperature in Sidney, Montana, United States of America is 14°C (57°F), with daytime highs ranging from -3°C (27°F) in December to 30°C (86°F) in July. This page covers monthly averages, day-night differences, and how Sidney compares to cities worldwide.

Visitors to Sidney can expect significant temperature changes throughout the year. Nighttime temperatures also vary widely, ranging from 14°C (57°F) in July to -14°C (7°F) in December.

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

Low temperatures are most often recorded between 4 AM and 6 AM, while highs typically occur around 3 PM.

The chart below shows the average temperature throughout the year:

Sidney's average annual maximum temperature is 14°C (57°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.

Glasgow, Scotland averages 13°C (55°F) a year, mild but often grey, with cold winters and rarely hot summers.

Shanghai, China averages 21°C (70°F) a year, with warm summers, mild winters, and a noticeable spring and autumn.

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 Sidney's weather, including monthly rainfall, sunshine hours, and humidity, visit our Sidney climate page.