Riverdale weather in September

In September, Riverdale sees average daytime highs of 83°F and overnight lows near 65°F, with 3.6 in of rain across 8.7 wet days and about 12.2 hours of daylight. It is the 4th-warmest and 9th-wettest month of the year here.

Highs ease over the month, from about 86°F in the first days to 79°F by the end. The sky is clear or mostly clear about 39% of the time in September, and the air most often feels muggy.

Daylight stretches from about 12 h 42 min at the start of September to 11 h 42 min by month's end. Set against the rest of the year, September is Riverdale's 3rd-clearest and 9th-windiest month. For the whole year in context, see Riverdale's year-round climate.

Daytime high
83°
4th warmest
Overnight low
65°
9th coldest
Rainfall
3.6 in
8.7 wet days
Daylight
12 h 12 min
6:26 AM – 6:38 PM
Cloud cover
53%
3rd clearest
Wind
5 mph
9th windiest
Solar energy
4.64 kWh/m²
Travel score
6.1
out of 10

Riverdale is city in Clayton County, Georgia, United States.

Density
1,359/km²
people per km²

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 86°F in the first days to 79°F by the end.

A typical September day in Riverdale reaches about 83°F in the afternoon and slips back to 65°F overnight — a 18°F spread between the day's warmth and the night's chill. On most days the high lands between 75°F and 90°F. Set against its neighbours, September runs about 5°F cooler than August and about 9°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
18669
28668
38668
48668
58568
68567
78567
88567
98567
108566
118466
128466
138465
148465
158365
168365
178364
188364
198264
208264
218263
228163
238162
248162
258062
268061
278061
287961
297960
307960

How September really feels in Riverdale

Once humidity and wind are folded in, September averages 0 days that feel above 90°F and 0 that feel at or below 32°F — the comfort signal a plain temperature reading hides.

Days feeling ≥ 90°F
0
heat index over the day's high
Days feeling ≤ 32°F
0
wind chill below the day's low

September sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Riverdale weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 9th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan54° / 35°4.010.10.6103.2
Feb58° / 38°4.39.60.310.84.2
Mar65° / 45°4.310.10.111.76.0
Apr73° / 52°3.28.5012.87.0
May81° / 61°2.99.4013.76.4
Jun86° / 69°3.714014.24.4
Jul89° / 72°4.215.50143.7
Aug88° / 71°3.813.2013.24.1
Sep83° / 65°3.68.7012.26.1
Oct74° / 53°2.86.7011.27.5
Nov64° / 43°3.77.9010.36.1
Dec56° / 38°4.1100.29.83.8

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 39% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 18% of September, with mostly cloudy or overcast conditions the remaining 44%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15446
25545
35644
45644
55743
65743
75842
85842
95842
105941
115941
125941
135941
145842
155842
165743
175644
185644
195545
205545
215446
225545
235446
245545
255545
265545
275545
285545
295644
305644

Chance of precipitation in September

Any precipitation

Riverdale gets around 3.6 in of rain over 8.7 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 28% and peaks near 35% on the wettest days. The odds ease toward the end of the month.

0%10%20%30%40%50%151015202530
Rain chance (%)
135
234
333
433
532
631
730
829
928
1028
1127
1227
1327
1426
1526
1626
1727
1827
1927
2027
2128
2228
2328
2428
2527
2627
2727
2826
2926
3025

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

Most of September feels muggy — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, September lands in the muggy band about 31% of days. Sticky, muggy-or-worse air turns up on roughly 44% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
138224225
249234123
349234122
4510244021
5611253919
6612253918
7712263817
8813263716
9914273615
101015273514
111115273413
121216273313
131216273212
141317273112
151417273012
161518263012
171518262911
181618262811
191718262811
201818262710
211918262610
222019262610
23221925259
24231925249
25251925238
26262024237
27272024227
28292024226
29302023215
30312123205

Wind in September

Winds average 5 mph in September.

Across September, daily wind ranges from about 5 mph on the calmest days to 6 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (mph)Feels
15calm
25calm
35calm
45calm
55calm
65calm
75calm
85calm
95calm
105calm
115calm
125calm
135calm
145calm
155calm
165calm
176calm
186calm
196calm
206calm
216calm
226calm
236calm
246calm
256calm
266calm
276calm
286calm
296calm
306calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 42 min at the start of September to 11 h 42 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 60 minutes over September. Sunrise moves from 6:15 AM to 6:36 AM, and sunset from 6:59 PM to 6:18 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.76:156:59
212.76:166:58
312.76:176:57
412.66:186:55
512.66:186:54
612.66:196:52
712.56:206:51
812.56:206:50
912.56:216:48
1012.46:226:47
1112.46:226:45
1212.36:236:44
1312.36:246:42
1412.36:246:41
1512.26:256:40
1612.26:266:38
1712.26:276:37
1812.16:276:35
1912.16:286:34
2012.16:296:32
2112.06:296:31
2212.06:306:29
2312.06:316:28
2411.96:316:27
2511.96:326:25
2611.86:336:24
2711.86:346:22
2811.86:346:21
2911.76:356:20
3011.76:366:18

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.64 kWh/m².

For context, solar energy here swings from a low near 2.35 kWh/m² to a high of 6.12 kWh/m² in May across the year — September's 4.64 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.0Bright
25.0Bright
35.0Bright
45.0Bright
55.0Bright
65.0Bright
74.9Bright
84.9Bright
94.9Bright
104.9Bright
114.8Bright
124.8Bright
134.8Bright
144.7Bright
154.7Bright
164.7Bright
174.6Bright
184.6Bright
194.5Bright
204.5Bright
214.5Bright
224.4Bright
234.4Bright
244.4Bright
254.3Bright
264.3Bright
274.3Bright
284.3Bright
294.2Bright
304.2Bright
Planning a trip in September

Is September a good time to visit Riverdale?

Our two travel scores rate September for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

6.1
Sightseeing
4th-best month of the year
7.0
Beach & pool
1st-best month of the year

September is a reasonable time to visit Riverdale for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Riverdale in September

From September's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In September, Riverdale sees daytime highs around 83°F and nights near 65°F. Pack light clothes. Worth having: rain gear and sun protection. About 9 days see rain.

light clothesrain gearsun protection

UV index in Riverdale in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Riverdale peaks around July 12 at about 10 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 19 at about 3 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 11 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateJul 12UV 10Dec 19UV 3
UV index (midday)Level
Jan3Moderate
Feb5Moderate
Mar5High
Apr7Very high
May8Very high
Jun9Very high
Jul10Very high
Aug9Very high
Sep7Very high
Oct5High
Nov4Moderate
Dec3Moderate

Air quality in Riverdale in September

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where September falls, not just the annual average.

Air quality in Riverdale is worst in July — around 21 µg/m³ PM2.5 (moderate), about 2.8× the cleanest month (January, 8 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateModerateGoodJul 1620 µg/m³Jan 118 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb10Good
Mar12Moderate
Apr12Good
May14Moderate
Jun17Moderate
Jul21Moderate
Aug17Moderate
Sep13Moderate
Oct10Good
Nov9Good
Dec8Good
Location & terrain

Where is Riverdale?

Riverdale sits at 33.6°N, 84.4°W, 925 ft above sea level, in United States. The nearest listed city is Forest Park, 4.3 mi away.

Topography around Riverdale

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Riverdale.

Within 2 miles, the terrain around Riverdale has only modest variations in elevation — a maximum elevation change of 554 ft around an average of 912 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 630 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 1,549 ft.

The land around Riverdale is covered by trees (65%) and artificial surfaces (23%) within 2 miles, trees (67%) and artificial surfaces (20%) within 10 miles, and trees (82%) within 50 miles.

2 miles
554 ft
10 miles
630 ft
50 miles
1,549 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Forest Park 4.3 mi · Union City 7.5 mi · East Point 7.5 mi · Fayetteville 8.7 mi · Stockbridge 11 mi · Atlanta 12 mi · Candler-McAfee 14 mi · South Fulton 15 mi

United States travel facts

Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 100% of US
price level, 2025
GDP per capita
$90,027
2025
Happiness
6.8 / 10
World Happiness, 2025
Safe drinking water
98%
of population, 2024
Homicide rate
5.8
per 100k, 2023
Road deaths
12.7
per 100k/yr, 2019
Income group
High
World Bank
Religion
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 2%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Riverdale (33.5726°, -84.4133°, elevation 925 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).