Marietta climate — normals and trends
Marietta (United States) has a humid subtropical climate (Cfa) under the Köppen-Geiger classification. Its mean annual temperature is 16.0 °C and it receives 1,210 mm of precipitation per year.
These figures are normals computed over 86 complete calendar years, from 1940 to 2025, using ERA5 reanalysis data from the Copernicus programme.
The warmest month is July (25.6 °C on average) and the coldest is January (5.5 °C). Rainfall peaks in March.
Marietta averages 43 frost days, 63 hot days (≥ 30 °C) and 126 rainy days per year.
Marietta has warmed by +1.3 °C between 1940 and 2025, or +0.15 °C per decade. This trend is statistically significant.
The hottest day of the period reached 40.4 °C (on 30 June 2012) and the coldest -22.3 °C (on 21 January 1985).
Data from ERA5 reanalysis (Copernicus Climate Change Service), redistributed under a CC-BY 4.0 licence. Normals are recomputed whenever the archive is updated.
Climate normals · ERA5
MariettaGeorgia
- coords
- 33.95°, -84.55°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
16.0°C
Average daily high
21.5°C
Average daily low
11.2°C
Annual rainfall
1,210mm
Sunshine / day
9.0h
Mean relative humidity
71%
Average peak wind
15.4km/h
Seasonal range
20.1°C
Frost days (< 0 °C)
43 d/yr
Hot days (≥ 30 °C)
63 d/yr
Rainy days (≥ 1 mm)
126 d/yr
Annual snowfall
6.0 cm
Average feels-like high
21.4 °C
Average feels-like low
9.9 °C
Average peak gust
35.2 km/h
Tropical nights (≥ 20 °C)
78 d/yr
Solar radiation
15.9 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.3 °C
since 1940
+0.2 °C per decade · r² = 0.27 · p = < 0.001
Trend fitted by linear regression (ordinary least squares) on annual means. A trend is shown only when it is statistically significant (p < 0.05).
A climograph overlays rainfall (bars) and temperature (line): the standard reading in climatology, where you can see at a glance whether the warm season is also the dry one.
Records for the period
Hottest day
40.4 °C
30 June 2012
Coldest day
-22.3 °C
21 January 1985
Wettest day
107 mm
17 September 2020
Windiest day
57.1 km/h
5 October 1995
Strongest gust
136.4 km/h
5 October 1995
Hottest feels-like
44.5 °C
30 June 2012
Coldest feels-like
-29.3 °C
21 January 1985
Snowiest day
20.7 cm
23 January 1940
Sunniest day
13.9 h
22 June 2022
Normals computed over complete calendar years 1940–2025.
A specific year
Pick a year and see how it compares to normal — warmer, drier or more extreme than usual?
Across the whole year
Month by month
| High | vs. normal | Precipitation | vs. normal | |
|---|---|---|---|---|
| Jan | 8.7 °C | -1.9 °C | 74 mm | -40 mm |
| Feb | 15.8 °C | +2.8 °C | 122 mm | +7 mm |
| Mar | 20.3 °C | +3.1 °C | 81 mm | -45 mm |
| Apr | 24.1 °C | +2.2 °C | 115 mm | +10 mm |
| May | 25.1 °C | -0.9 °C | 196 mm | +104 mm |
| Jun | 29.8 °C | +0.3 °C | 132 mm | +40 mm |
| Jul | 32.6 °C | +1.9 °C | 93 mm | -18 mm |
| Aug | 28.5 °C | -1.8 °C | 113 mm | +21 mm |
| Sep | 28.8 °C | +1.3 °C | 32 mm | -55 mm |
| Oct | 22.6 °C | +0.3 °C | 59 mm | -16 mm |
| Nov | 18.9 °C | +2.3 °C | 44 mm | -50 mm |
| Dec | 13.9 °C | +1.9 °C | 38 mm | -70 mm |
The year's extremes
What was the weather like that day?
Your birthday, a wedding, a memorable trip: discover the actual weather for any date since 1940.
Frequently asked questions
What is the climate of Marietta?
Marietta has a humid subtropical climate (Köppen Cfa). Over 1940-2025, the average annual temperature is 16.0 °C and it receives 1,210 mm of precipitation per year.
What is the hottest day ever recorded in Marietta?
The hottest day measured in Marietta between 1940 and 2025 was 30 June 2012, reaching 40.4 °C.
What is the coldest day in Marietta?
The coldest day measured in Marietta between 1940 and 2025 was 21 January 1985, at -22.3 °C.
Does it snow in Marietta?
Yes. Marietta gets on average 6.0 cm of snow per year and has around 43 frost days.
Has the climate of Marietta warmed?
Yes: Marietta warmed by +1.3 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Marietta?
The wettest day measured in Marietta between 1940 and 2025 was 17 September 2020, with 107 mm of rain in 24 hours.
What was the windiest day in Marietta?
The windiest day measured in Marietta between 1940 and 2025 was 5 October 1995, with winds reaching 57.1 km/h.
What is the warmest month in Marietta?
The warmest month in Marietta is July (25.6 °C on average); the coldest is January (5.5 °C).
How much does it rain in Marietta?
Marietta receives on average 1,210 mm of precipitation per year, spread over about 126 rainy days.
Is it sunny in Marietta?
Marietta gets on average 9.0 hours of sunshine per day, roughly 3,285 hours per year over 1940-2025.
What is the biggest single-day snowfall in Marietta?
The heaviest 24-hour snowfall measured in Marietta between 1940 and 2025 was 23 January 1940, with 20.7 cm.
Are there tropical nights in Marietta?
Yes: Marietta has on average 78 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Marietta?
In Marietta, between 1940 and 2025, the highest apparent temperature reached 44.5 °C on 30 June 2012, and the lowest was -29.3 °C on 21 January 1985.
Compare Marietta with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Marietta