McKinney weather in September

In September, McKinney sees average daytime highs of 87°F and overnight lows near 68°F, with 3.1 in of rain across 6.8 wet days and about 12.2 hours of daylight. It is the 4th-warmest and 8th-wettest month of the year here.

Highs ease over the month, from about 90°F in the first days to 83°F by the end. The sky is clear or mostly clear about 55% 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 McKinney's 1st-clearest and 11th-windiest month. For the whole year in context, see McKinney's year-round climate.

Daytime high
87°
4th warmest
Overnight low
68°
9th coldest
Rainfall
3.1 in
6.8 wet days
Daylight
12 h 12 min
6:15 AM – 6:27 PM
Cloud cover
41%
1st clearest
Wind
7 mph
11th windiest
Solar energy
5.11 kWh/m²
Travel score
5.4
out of 10

McKinney is city in Collin County, Texas, United States.

Density
988/km²
people per km²
Founded
1848

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 90°F in the first days to 83°F by the end.

A typical September day in McKinney reaches about 87°F in the afternoon and slips back to 68°F overnight — a 19°F spread between the day's warmth and the night's chill. On most days the high lands between 78°F and 94°F. Set against its neighbours, September runs about 7°F cooler than August and about 10°F warmer than October.

60°80°100°151015202530
Avg high (°F)Avg low (°F)
19173
29172
39072
49072
59071
68971
78971
88971
98870
108870
118870
128769
138769
148769
158768
168668
178667
188667
198567
208566
218566
228565
238465
248465
258464
268464
278364
288363
298363
308262

How September really feels in McKinney

Once humidity and wind are folded in, September averages 9 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
9
heat index over the day's high
Days feeling ≤ 32°F
0
wind chill below the day's low

The story in September is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

McKinney weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 8th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan55° / 37°2.86.80.510.13.8
Feb59° / 40°2.97.50.610.84.8
Mar66° / 47°4.19.50.311.76.2
Apr74° / 55°4.69.2012.87.0
May81° / 64°5.711.5013.76.1
Jun89° / 72°3.69.1014.24.4
Jul93° / 75°2.06.20143.4
Aug93° / 75°2.05.8013.23.4
Sep87° / 68°3.16.8012.25.4
Oct76° / 57°4.17.9011.27.4
Nov65° / 46°3.77.2010.36.4
Dec56° / 39°3.87.20.39.84.2

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 55% of the time in September, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 14% of September, with mostly cloudy or overcast conditions the remaining 30%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
17228
27129
37129
46931
56931
66832
76832
86733
96733
106733
116634
126733
136733
146634
156634
166733
176733
186733
196832
206832
217030
227129
237129
247327
257327
267426
277426
287426
297525
307426

Chance of precipitation in September

Any precipitation

McKinney gets around 3.1 in of rain over 6.8 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 23% and peaks near 26% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
122
223
324
424
525
625
726
826
926
1026
1126
1226
1326
1426
1525
1625
1724
1824
1923
2022
2121
2220
2320
2419
2518
2618
2718
2818
2919
3019

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 30% of days. Sticky, muggy-or-worse air turns up on roughly 49% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
149233926
259233725
3610233625
4710233525
5710223525
6811223524
7911223424
81011213424
91011213424
101111203423
111211203423
121212193423
131312193322
141413193322
151413193321
161513183320
171614183219
181714183119
191915183018
202015182917
212216182816
222416182715
232617182514
242817182413
253017182312
263218182111
273318182010
283518191910
29371819189
30381819179

Wind in September

Winds average 7 mph in September.

Across September, daily wind ranges from about 7 mph on the calmest days to 8 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (mph)Feels
17calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
227calm
237calm
247calm
257calm
267calm
277light breeze
288light breeze
298light breeze
308light breeze

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 6:05 AM to 6:24 AM, and sunset from 6:48 PM to 6:07 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.76:056:48
212.76:056:46
312.76:066:45
412.66:076:44
512.66:076:42
612.66:086:41
712.56:096:40
812.56:096:38
912.46:106:37
1012.46:116:35
1112.46:116:34
1212.36:126:33
1312.36:136:31
1412.36:136:30
1512.26:146:28
1612.26:156:27
1712.26:156:25
1812.16:166:24
1912.16:176:23
2012.16:176:21
2112.06:186:20
2212.06:196:18
2312.06:206:17
2411.96:206:15
2511.96:216:14
2611.96:226:13
2711.86:226:11
2811.86:236:10
2911.76:246:08
3011.76:246:07

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 5.11 kWh/m².

For context, solar energy here swings from a low near 2.52 kWh/m² to a high of 6.77 kWh/m² in July across the year — September's 5.11 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.6Bright
25.6Bright
35.5Bright
45.5Bright
55.4Bright
65.4Bright
75.4Bright
85.3Bright
95.3Bright
105.2Bright
115.2Bright
125.2Bright
135.1Bright
145.1Bright
155.1Bright
165.0Bright
175.0Bright
185.0Bright
195.0Bright
205.0Bright
215.0Bright
224.9Bright
234.9Bright
244.9Bright
254.9Bright
264.9Bright
274.8Bright
284.8Bright
294.8Bright
304.8Bright
Planning a trip in September

Is September a good time to visit McKinney?

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

5.4
Sightseeing
6th-best month of the year
7.4
Beach & pool
1st-best month of the year

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

What to pack for McKinney in September

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

In September, McKinney sees daytime highs around 87°F and nights near 68°F. Pack light clothes. Worth having: sun protection. About 7 days see rain.

light clothessun protection

UV index in McKinney in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 8 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in McKinney peaks around July 17 at about 10 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 at about 3 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highExtremeVery highHighModerateJul 17UV 10Dec 21UV 3
UV index (midday)Level
Jan3Moderate
Feb5Moderate
Mar6High
Apr9Very high
May9Very high
Jun10Very high
Jul10Extreme
Aug10Very high
Sep8Very high
Oct6High
Nov4Moderate
Dec3Moderate

Air quality in McKinney 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 McKinney is worst in July — around 19 µg/m³ PM2.5 (moderate), about 2.6× the cleanest month (October, 8 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1519 µg/m³Oct 248 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb8Good
Mar10Good
Apr11Good
May14Moderate
Jun16Moderate
Jul19Moderate
Aug15Moderate
Sep11Good
Oct8Good
Nov8Good
Dec8Good
Location & terrain

Where is McKinney?

McKinney sits at 33.2°N, 96.6°W, 630 ft above sea level, in United States. The nearest listed city is Allen, 7.5 mi away.

Topography around McKinney

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

Within 2 miles, the terrain around McKinney has only modest variations in elevation — a maximum elevation change of 164 ft around an average of 594 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 318 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 722 ft.

The land around McKinney is covered by artificial surfaces (38%), trees (27%) and grassland (24%) within 2 miles, grassland (37%), trees (24%) and artificial surfaces (22%) within 10 miles, and grassland (47%) and trees (26%) within 50 miles.

2 miles
164 ft
10 miles
318 ft
50 miles
722 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Allen 7.5 mi · Prosper 11 mi · Frisco 12 mi · Murphy 12 mi · Celina 13 mi · Plano 13 mi · Wylie 14 mi · The Trails of Frisco 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 McKinney (33.1976°, -96.6153°, elevation 630 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).