Marietta (GA) Temperature by Month

Marietta in Georgia, United States of America sees significant seasonal temperature differences, with daytime highs between 11°C (52°F) in January and 31°C (88°F) in July, averaging 22°C (72°F) annually. Explore the full monthly breakdown below.

Visitors to Marietta will encounter a climate influenced by big temperature differences across the year. Nighttime temperatures range from 21°C (70°F) in July to -1°C (30°F) in January.

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

Temperatures tend to bottom out between 4 AM and 6 AM, then climb to their daily peak around 3 PM. July, the warmest month, sees 273 hours of sunshine.

The chart below shows the average temperature throughout the year:

Marietta's average annual maximum temperature is 22°C (72°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.

Interlaken, Switzerland averages 8°C (46°F) a year, with cold winters and cool summers thanks to its Alpine setting.

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

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

Temperature alone doesn't tell the whole story, humidity plays a big role in how warm or cold it actually feels. High humidity in summer makes the heat feel more intense, particularly once temperatures climb above 25°C. In winter, the same humidity can make cold air feel sharper than the thermometer suggests.

In the cooler months, when temperatures drop below 10°C, high humidity makes the cold feel more cutting than it would in dry conditions.

In Marietta, January is the coolest month, with average highs of 11°C (52°F) and humidity around 67%, considered high. In July, the warmest month, temperatures average 31°C (88°F) with 74% humidity, conditions that feel high. For a full picture, see our humidity page.

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.

For cities and regions with significant elevation, altitude is one of the biggest factors shaping local temperatures. As a rule of thumb, temperatures fall by around 6°C for every 1,000 metres gained, so a city at 2,000 metres will typically be around 12°C cooler than a city at sea level in the same region. Higher ground also tends to see more dramatic day-to-night temperature swings, since thinner air loses heat faster after sunset.

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