Greater Upper Marlboro weather in September

In September, Greater Upper Marlboro sees average daytime highs of 78°F and overnight lows near 64°F, with 4.3 in of rain across 9.1 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 2nd-wettest month of the year here.

Highs ease over the month, from about 82°F in the first days to 74°F by the end. The sky is clear or mostly clear about 35% of the time in September, and the air most often feels dry.

Daylight stretches from about 12 h 54 min at the start of September to 11 h 36 min by month's end. Set against the rest of the year, September is Greater Upper Marlboro's 3rd-clearest and 9th-windiest month. For the whole year in context, see Greater Upper Marlboro's year-round climate.

Daytime high
78°
4th warmest
Overnight low
64°
9th coldest
Rainfall
4.3 in
9.1 wet days
Daylight
12 h 12 min
5:54 AM – 6:09 PM
Cloud cover
56%
3rd clearest
Wind
6 mph
9th windiest
Solar energy
4.31 kWh/m²
Travel score
6.9
out of 10

Greater Upper Marlboro is census designated place in Maryland until 2010.

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 82°F in the first days to 74°F by the end.

A typical September day in Greater Upper Marlboro reaches about 78°F in the afternoon and slips back to 64°F overnight — a 14°F spread between the day's warmth and the night's chill. On most days the high lands between 70°F and 87°F. Set against its neighbours, September runs about 6°F cooler than August and about 11°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
18368
28268
38268
48268
58267
68167
78167
88166
98066
108066
118065
127965
137965
147964
157864
167864
177863
187763
197763
207762
217662
227662
237661
247561
257560
267560
277460
287459
297459
307359

How September really feels in Greater Upper Marlboro

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.

Greater Upper Marlboro weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 2nd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan44° / 30°3.18.62.69.60.7
Feb46° / 31°2.98.62.410.51.4
Mar55° / 38°4.010.31.511.73.4
Apr66° / 49°3.4100.1135.9
May74° / 58°3.710.7014.16.6
Jun83° / 67°3.711014.75.7
Jul87° / 72°4.312.3014.44.5
Aug85° / 71°4.010.6013.55.3
Sep78° / 64°4.39.1012.36.9
Oct67° / 52°3.57.90116.6
Nov56° / 42°2.97.60.19.94.2
Dec47° / 35°3.58.81.29.31.7

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 35% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 17% of September, with mostly cloudy or overcast conditions the remaining 48%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15347
25347
35347
45347
55347
65347
75446
85446
95446
105446
115446
125347
135347
145347
155248
165248
175149
185050
195050
205050
214951
224951
235050
245050
255149
265248
275248
285248
295347
305347

Chance of precipitation in September

Any precipitation

Greater Upper Marlboro gets around 4.3 in of rain over 9.1 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 29% and peaks near 31% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
130
231
331
431
531
631
730
830
930
1029
1129
1228
1328
1427
1527
1627
1727
1827
1927
2028
2128
2228
2329
2429
2529
2628
2728
2828
2928
3028

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the dry band about 24% of days. Sticky, muggy-or-worse air turns up on roughly 34% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
17142628241
28142727231
39152726231
410152726221
511152725211
612162724201
713162724191
814172723181
915172723161
1016172723151
1118182723141
1219182723131
1320182723120
1422182623110
1523182623100
162419252390
172619252380
182719242370
192819242360
203019232350
213119232250
223319222240
233419222240
243619212130
253719202030
263919202030
274019191930
284218191830
294418181730
304518181630

Wind in September

Winds average 6 mph in September.

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

0246810151015202530
Wind speed (mph)Feels
16calm
26calm
36calm
46calm
56calm
66calm
76calm
86calm
96calm
106calm
116calm
126calm
136calm
146calm
156calm
166calm
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 54 min at the start of September to 11 h 36 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 78 minutes over September. Sunrise moves from 5:40 AM to 6:07 AM, and sunset from 6:33 PM to 5:46 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.95:406:33
212.85:416:32
312.85:426:30
412.85:436:29
512.75:446:27
612.75:456:25
712.65:466:24
812.65:466:22
912.55:476:20
1012.55:486:19
1112.55:496:17
1212.45:506:15
1312.45:516:14
1412.35:526:12
1512.35:536:10
1612.25:546:09
1712.25:556:07
1812.25:566:05
1912.15:576:04
2012.15:586:02
2112.05:586:00
2212.05:595:59
2311.96:005:57
2411.96:015:55
2511.96:025:54
2611.86:035:52
2711.86:045:51
2811.76:055:49
2911.76:065:47
3011.66:075:46

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.31 kWh/m².

For context, solar energy here swings from a low near 1.98 kWh/m² to a high of 6.16 kWh/m² in June across the year — September's 4.31 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.9Bright
24.8Bright
34.8Bright
44.8Bright
54.7Bright
64.7Bright
74.7Bright
84.6Bright
94.6Bright
104.5Bright
114.5Bright
124.5Bright
134.4Bright
144.4Bright
154.4Bright
164.3Bright
174.3Bright
184.2Bright
194.2Bright
204.2Bright
214.1Bright
224.1Bright
234.0Bright
244.0Bright
254.0Moderate
263.9Moderate
273.9Moderate
283.9Moderate
293.9Moderate
303.8Moderate
Planning a trip in September

Hazard calendar for Greater Upper Marlboro

In seasonPeak

In September, Greater Upper Marlboro sits inside its atlantic hurricane season. The full year is below, with each hazard's peak months called out.

Greater Upper Marlboro sits in the Atlantic hurricane belt; the season peaks August–October.

Atlantic hurricane
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is September a good time to visit Greater Upper Marlboro?

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

6.9
Sightseeing
1st-best month of the year
6.4
Beach & pool
4th-best month of the year

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

What to pack for Greater Upper Marlboro in September

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

In September, Greater Upper Marlboro sees daytime highs around 78°F and nights near 64°F. Worth packing: light clothes and rain gear. About 9 days see rain.

light clothesrain gear

Sea temperature near Greater Upper Marlboro in September

The nearest coast averages about 74°F in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 21 mi away) is warmest in August at about 78°F and coldest in February near 37°F.

It's comfortable for a long swim from Jun 16 to Oct 6 — about 3.7 months when the water holds above 68°F.

30°40°50°60°70°80°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°F)Comfort
Jan38Bracing
Feb37Bracing
Mar40Bracing
Apr47Bracing
May58Bracing
Jun68Refreshing
Jul76Warm
Aug78Warm
Sep74Refreshing
Oct65Cool
Nov54Bracing
Dec45Bracing

UV index in Greater Upper Marlboro in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 6 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Greater Upper Marlboro peaks around July 11 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 19 at about 2 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 9 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateLowJul 11UV 9Dec 19UV 2
UV index (midday)Level
Jan2Moderate
Feb3Moderate
Mar5Moderate
Apr6High
May8Very high
Jun9Very high
Jul9Very high
Aug7High
Sep6High
Oct4Moderate
Nov3Moderate
Dec2Low

Air quality in Greater Upper Marlboro 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 Greater Upper Marlboro is worst in July — around 17 µg/m³ PM2.5 (moderate), about 2.0× the cleanest month (November, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1216 µg/m³Nov 118 µg/m³
PM2.5 (µg/m³)Level
Jan10Good
Feb12Good
Mar13Moderate
Apr13Moderate
May15Moderate
Jun16Moderate
Jul17Moderate
Aug14Moderate
Sep12Good
Oct9Good
Nov8Good
Dec10Good
Location & terrain

Where is Greater Upper Marlboro?

Greater Upper Marlboro sits at 38.8°N, 76.7°W, 79 ft above sea level, in United States. The nearest listed city is Bowie, 7.5 mi away.

Topography around Greater Upper Marlboro

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

Within 2 miles, the terrain around Greater Upper Marlboro has only modest variations in elevation — a maximum elevation change of 276 ft around an average of 115 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 341 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 1,434 ft.

The land around Greater Upper Marlboro is covered by trees (75%) within 2 miles, trees (68%) within 10 miles, and trees (55%) and water (21%) within 50 miles.

2 miles
276 ft
10 miles
341 ft
50 miles
1,434 ft
treesgrasslandcroplandartificial surfaceswaterwetland
September weather nearby: Bowie 7.5 mi · Camp Springs 8.7 mi · Clinton 9.3 mi · Suitland 9.3 mi · Suitland-Silver Hill 9.3 mi · Landover 11 mi · Lanham-Seabrook 11 mi · Seabrook 11 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 Greater Upper Marlboro (38.8314°, -76.7483°, elevation 79 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. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. 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).