Apex weather in September

In September, Apex sees average daytime highs of 81°F and overnight lows near 64°F, with 4.7 in of rain across 10.2 wet days and about 12.2 hours of daylight. It is the 4th-warmest and 1st-wettest month of the year here.

Highs ease over the month, from about 84°F in the first days to 77°F by the end. The sky is clear or mostly clear about 34% of the time in September, and the air most often feels muggy.

Daylight stretches from about 12 h 48 min at the start of September to 11 h 42 min by month's end. Set against the rest of the year, September is Apex's 6th-clearest and 9th-windiest month. For the whole year in context, see Apex's year-round climate.

Daytime high
81°
4th warmest
Overnight low
64°
9th coldest
Rainfall
4.7 in
10.2 wet days
Daylight
12 h 12 min
6:03 AM – 6:16 PM
Cloud cover
56%
6th clearest
Wind
6 mph
9th windiest
Solar energy
4.44 kWh/m²
Travel score
6.3
out of 10

Apex is town in Wake County, North Carolina, United States of America.

Density
1,140/km²
people per km²
Founded
1873

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 84°F in the first days to 77°F by the end.

A typical September day in Apex reaches about 81°F in the afternoon and slips back to 64°F overnight — a 17°F spread between the day's warmth and the night's chill. On most days the high lands between 73°F and 89°F. Set against its neighbours, September runs about 6°F cooler than August and about 9°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
18568
28568
38568
48467
58467
68467
78367
88366
98366
108366
118265
128265
138265
148265
158164
168164
178164
188064
198063
208063
218063
227962
237962
247962
257861
267861
277861
287760
297760
307759

How September really feels in Apex

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.

Apex 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
Jan51° / 34°3.79.31.29.92.7
Feb55° / 36°3.291.310.63.4
Mar62° / 42°4.110.40.511.75.4
Apr72° / 51°3.59.1012.96.8
May79° / 60°3.510.4013.96.6
Jun86° / 68°4.112.1014.44.8
Jul89° / 72°4.615.2014.23.7
Aug87° / 70°4.412.4013.44.5
Sep81° / 64°4.710.2012.26.3
Oct72° / 53°3.17.2011.17.2
Nov62° / 42°3.37.70.110.15.7
Dec54° / 37°3.69.10.69.63.4

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 34% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 19% of September, with mostly cloudy or overcast conditions the remaining 47%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15347
25347
35347
45446
55446
65545
75545
85545
95545
105545
115644
125545
135545
145446
155347
165347
175248
185149
195149
205050
215050
225050
235050
245050
255149
265149
275149
285248
295347
305347

Chance of precipitation in September

Any precipitation

Apex gets around 4.7 in of rain over 10.2 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 32% and peaks near 35% on the wettest days.

0%10%20%30%40%50%151015202530
Rain chance (%)
135
235
335
434
534
633
733
833
932
1032
1131
1231
1331
1431
1531
1631
1732
1832
1933
2033
2133
2234
2334
2433
2533
2632
2731
2831
2930
3030

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 29% of days. Sticky, muggy-or-worse air turns up on roughly 45% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
13122033311
24122133301
34132132291
45132132281
56142232270
67142231250
77142331240
88152331230
99152331220
1010152331200
1111162331190
1212162331180
1313162331170
1414162331160
1515172330150
1615172330140
1716182230140
1817182230130
1917182230120
2018192229120
2119192229110
2220192228100
2322202127100
242320212690
252420212590
262621212480
272721212380
282921212280
293021212170
303221201970

Wind in September

Winds average 6 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
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 48 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 66 minutes over September. Sunrise moves from 5:51 AM to 6:14 AM, and sunset from 6:39 PM to 5:55 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.85:516:39
212.85:526:37
312.75:536:36
412.75:546:35
512.65:546:33
612.65:556:32
712.65:566:30
812.55:576:29
912.55:586:27
1012.55:586:26
1112.45:596:24
1212.46:006:23
1312.36:016:21
1412.36:016:19
1512.36:026:18
1612.26:036:16
1712.26:046:15
1812.16:056:13
1912.16:056:12
2012.16:066:10
2112.06:076:09
2212.06:086:07
2312.06:096:06
2411.96:096:04
2511.96:106:03
2611.86:116:01
2711.86:126:00
2811.86:135:58
2911.76:135:57
3011.76:145:55

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.44 kWh/m².

For context, solar energy here swings from a low near 2.26 kWh/m² to a high of 6.17 kWh/m² in June across the year — September's 4.44 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
15.0Bright
24.9Bright
34.9Bright
44.9Bright
54.8Bright
64.8Bright
74.8Bright
84.7Bright
94.7Bright
104.7Bright
114.6Bright
124.6Bright
134.5Bright
144.5Bright
154.5Bright
164.4Bright
174.4Bright
184.3Bright
194.3Bright
204.3Bright
214.2Bright
224.2Bright
234.2Bright
244.1Bright
254.1Bright
264.1Bright
274.1Bright
284.0Bright
294.0Bright
304.0Moderate
Planning a trip in September

Is September a good time to visit Apex?

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

6.3
Sightseeing
4th-best month of the year
6.7
Beach & pool
1st-best month of the year

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

What to pack for Apex in September

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

In September, Apex sees daytime highs around 81°F and nights near 64°F. Pack light clothes. Worth having: rain gear. About 10 days see rain.

light clothesrain gear

UV index in Apex 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 Apex peaks around July 13 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 20 at about 2 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 10 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateJul 13UV 9Dec 20UV 2
UV index (midday)Level
Jan3Moderate
Feb4Moderate
Mar6High
Apr7High
May8Very high
Jun9Very high
Jul9Very high
Aug8Very high
Sep7High
Oct5Moderate
Nov4Moderate
Dec2Moderate

Air quality in Apex 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 Apex is worst in July — around 18 µg/m³ PM2.5 (moderate), about 2.3× the cleanest month (November, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1718 µg/m³Nov 238 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb10Good
Mar12Moderate
Apr12Moderate
May13Moderate
Jun16Moderate
Jul18Moderate
Aug16Moderate
Sep12Good
Oct9Good
Nov8Good
Dec8Good
Location & terrain

Where is Apex?

Apex sits at 35.7°N, 78.9°W, 499 ft above sea level, in United States. The nearest listed city is Cary, 5.6 mi away.

Topography around Apex

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

Within 2 miles, the terrain around Apex has only modest variations in elevation — a maximum elevation change of 243 ft around an average of 440 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 604 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 1,119 ft.

The land around Apex is covered by trees (62%) and artificial surfaces (26%) within 2 miles, trees (71%) within 10 miles, and trees (75%) within 50 miles.

2 miles
243 ft
10 miles
604 ft
50 miles
1,119 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Cary 5.6 mi · Holly Springs 5.6 mi · Morrisville 6.2 mi · Fuquay-Varina 11 mi · West Raleigh 11 mi · Raleigh 12 mi · Garner 13 mi · Chapel Hill 17 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 Apex (35.7326°, -78.8503°, elevation 499 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).