Westminster weather in September

In September, Westminster sees average daytime highs of 77°F and overnight lows near 60°F, with 4.5 in of rain across 9.3 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 1st-wettest month of the year here.

Highs ease over the month, from about 81°F in the first days to 72°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 Westminster's 2nd-clearest and 9th-windiest month. For the whole year in context, see Westminster's year-round climate.

Daytime high
77°
4th warmest
Overnight low
60°
9th coldest
Rainfall
4.5 in
9.3 wet days
Daylight
12 h 18 min
5:55 AM – 6:10 PM
Cloud cover
56%
2nd clearest
Wind
6 mph
9th windiest
Solar energy
4.27 kWh/m²
Travel score
6.9
out of 10

Westminster is city in Carroll County, northern Maryland, United States.

Density
1,085/km²
people per km²
Founded
1764

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 81°F in the first days to 72°F by the end.

A typical September day in Westminster reaches about 77°F in the afternoon and slips back to 60°F overnight — a 17°F spread between the day's warmth and the night's chill. On most days the high lands between 67°F and 86°F. Set against its neighbours, September runs about 7°F cooler than August and about 12°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
18164
28164
38164
48164
58063
68063
78063
87962
97962
107962
117861
127861
137860
147760
157760
167659
177659
187659
197558
207558
217558
227457
237457
247456
257356
267356
277355
287255
297255
307154

How September really feels in Westminster

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.

Westminster weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 1st-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan40° / 26°3.28.83.59.50.0
Feb43° / 28°2.88.73.710.40.5
Mar52° / 35°3.910.52.611.72.7
Apr64° / 45°3.510.50.2135.4
May72° / 55°3.711.7014.16.4
Jun81° / 64°3.611.1014.75.9
Jul86° / 68°3.911.1014.55.0
Aug83° / 67°3.510.3013.65.7
Sep77° / 60°4.59.3012.36.9
Oct65° / 48°3.58010.96.2
Nov54° / 38°3.17.80.49.83.4
Dec44° / 31°3.68.92.19.30.8

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 16% of September, with mostly cloudy or overcast conditions the remaining 49%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15248
25149
35149
45149
55149
65248
75248
85248
95248
105248
115248
125248
135149
145149
155050
165149
174951
184951
195050
205050
214951
224951
234951
245149
255149
265248
275248
285347
295347
305446

Chance of precipitation in September

Any precipitation

Westminster gets around 4.5 in of rain over 9.3 wet days in September, the wettest month. 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 (%)
131
231
331
431
530
630
730
829
929
1029
1128
1228
1327
1427
1527
1627
1728
1828
1929
2029
2130
2230
2331
2431
2531
2631
2730
2830
2930
3030

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 39% of days. Sticky, muggy-or-worse air turns up on roughly 20% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1202521268
2212521258
3222520258
4232520248
5252519238
6262519228
7272519227
8292518217
9302518206
10312519205
11332419195
12342419194
13352419184
14372419173
15382419173
16392319162
17412319152
18422319142
19432318141
20442318131
21452318131
22472317121
23482317121
24512216110
25512216110
26532116100
27532116100
28552015100
2957191590
3058181590

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 6:08 AM, and sunset from 6:35 PM to 5:46 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.95:406:35
212.95:416:33
312.85:426:32
412.85:436:30
512.75:446:28
612.75:456:27
712.75:466:25
812.65:476:24
912.65:486:22
1012.55:496:20
1112.55:506:18
1212.45:516:17
1312.45:526:15
1412.35:536:13
1512.35:546:12
1612.35:556:10
1712.25:566:08
1812.25:576:07
1912.15:586:05
2012.15:586:03
2112.05:596:01
2212.06:006:00
2311.96:015:58
2411.96:025:56
2511.96:035:55
2611.86:045:53
2711.86:055:51
2811.76:065:50
2911.76:075:48
3011.66:085:46

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.27 kWh/m².

For context, solar energy here swings from a low near 1.88 kWh/m² to a high of 6.13 kWh/m² in June across the year — September's 4.27 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.8Bright
24.8Bright
34.8Bright
44.7Bright
54.7Bright
64.7Bright
74.6Bright
84.6Bright
94.5Bright
104.5Bright
114.5Bright
124.4Bright
134.4Bright
144.4Bright
154.3Bright
164.3Bright
174.2Bright
184.2Bright
194.2Bright
204.1Bright
214.1Bright
224.0Bright
234.0Bright
244.0Moderate
253.9Moderate
263.9Moderate
273.9Moderate
283.8Moderate
293.8Moderate
303.8Moderate
Planning a trip in September

Is September a good time to visit Westminster?

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
6.1
Beach & pool
4th-best month of the year

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

What to pack for Westminster in September

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

In September, Westminster sees daytime highs around 77°F and nights near 60°F. Worth packing: light clothes and rain gear. About 9 days see rain.

light clothesrain gear

UV index in Westminster 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 Westminster peaks around July 10 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 20 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 10UV 9Dec 20UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May8Very high
Jun9Very high
Jul9Very high
Aug7High
Sep6High
Oct3Moderate
Nov3Moderate
Dec2Low

Air quality in Westminster 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 Westminster is worst in July — around 17 µg/m³ PM2.5 (moderate), about 2.1× the cleanest month (November, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1317 µg/m³Nov 138 µg/m³
PM2.5 (µg/m³)Level
Jan10Good
Feb11Good
Mar12Moderate
Apr12Moderate
May15Moderate
Jun16Moderate
Jul17Moderate
Aug14Moderate
Sep12Good
Oct9Good
Nov8Good
Dec9Good
Location & terrain

Where is Westminster?

Westminster sits at 39.6°N, 77.0°W, 764 ft above sea level, in United States. The nearest listed city is Reisterstown, 11 mi away.

Topography around Westminster

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

Within 2 miles, the terrain around Westminster has only modest variations in elevation — a maximum elevation change of 397 ft around an average of 751 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 1,102 ft; within 50 miles, large variations in elevation — a maximum elevation change of 2,260 ft.

The land around Westminster is covered by trees (46%) and grassland (29%) within 2 miles, trees (47%), grassland (27%) and cropland (23%) within 10 miles, and trees (53%) within 50 miles.

2 miles
397 ft
10 miles
1,102 ft
50 miles
2,260 ft
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Reisterstown 11 mi · Eldersburg 12 mi · Hanover 16 mi · Owings Mills 16 mi · Randallstown 18 mi · Hunt Valley 20 mi · Milford Mill 20 mi · Cockeysville 20 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 Westminster (39.5754°, -76.9958°, elevation 764 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).