Meridian weather in September

In September, Meridian sees average daytime highs of 81°F and overnight lows near 54°F, with 0.4 in of rain across 2 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 10th-wettest month of the year here.

Highs ease over the month, from about 86°F in the first days to 75°F by the end. The sky is clear or mostly clear about 67% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 h 06 min at the start of September to 11 h 36 min by month's end. Set against the rest of the year, September is Meridian's 3rd-clearest and 11th-windiest month. For the whole year in context, see Meridian's year-round climate.

Daytime high
81°
4th warmest
Overnight low
54°
9th coldest
Rainfall
0.4 in
2 wet days
Daylight
12 h 18 min
6:31 AM – 6:49 PM
Cloud cover
29%
3rd clearest
Wind
5 mph
11th windiest
Solar energy
5.47 kWh/m²
Travel score
7.9
out of 10

Meridian is city in Ada County, Idaho, United States.

Density
1,176/km²
people per km²
Founded
1893

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 75°F by the end.

A typical September day in Meridian reaches about 81°F in the afternoon and slips back to 54°F overnight — a 27°F spread between the day's warmth and the night's chill. On most days the high lands between 68°F and 91°F. Set against its neighbours, September runs about 11°F cooler than August and about 15°F warmer than October.

40°60°80°100°151015202530
Avg high (°F)Avg low (°F)
18758
28658
38658
48557
58557
68557
78456
88456
98356
108355
118255
128255
138255
148154
158154
168053
178053
188053
197953
207952
217852
227852
237851
247751
257751
267651
277650
287550
297549
307449

How September really feels in Meridian

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.

Meridian weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 10th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan41° / 28°1.694.19.10.1
Feb47° / 31°1.07.32.210.21.6
Mar57° / 37°1.28.60.711.64.1
Apr64° / 42°1.16.40.113.26.2
May74° / 49°1.15.9014.57.5
Jun83° / 56°0.63.4015.27.0
Jul93° / 64°0.11014.94.0
Aug91° / 62°0.10.9013.84.6
Sep81° / 54°0.42012.37.9
Oct66° / 43°0.84.2010.87.0
Nov50° / 34°1.27.31.49.52.5
Dec40° / 28°1.69.348.80.1

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 67% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 14% of September, with mostly cloudy or overcast conditions the remaining 19%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
18713
28614
38614
48614
58515
68515
78317
88317
98218
108218
118119
128119
138020
147921
157921
167921
177822
187921
197921
207822
217822
227921
237921
247822
257822
267822
277822
287822
297723
307723

Chance of precipitation in September

Any precipitation

Meridian gets around 0.4 in of rain over 2 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 7% and peaks near 8% on the wettest days.

0%10%20%30%151015202530
Rain chance (%)
15
25
35
45
55
66
76
86
96
106
116
126
137
147
157
167
177
187
197
207
217
227
237
247
258
268
278
288
298
308

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 99% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)
1991
2982
3982
4982
5982
6982
7982
8982
9982
10991
11991
12991
13991
14991
15991
16991
171000
181000
191000
201000
211000
221000
231000
241000
251000
261000
271000
281000
291000
301000

Wind in September

Winds average 5 mph in September.

Across September, daily wind ranges from about 5 mph on the calmest days to 5 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
175calm
185calm
195calm
205calm
215calm
225calm
235calm
245calm
255calm
265calm
275calm
285calm
295calm
305calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 06 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 90 minutes over September. Sunrise moves from 6:14 AM to 6:48 AM, and sunset from 7:17 PM to 6:22 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.16:147:17
213.06:157:15
313.06:167:13
412.96:177:11
512.96:187:09
612.86:197:08
712.86:217:06
812.76:227:04
912.76:237:02
1012.66:247:00
1112.56:256:58
1212.56:266:56
1312.46:286:54
1412.46:296:53
1512.36:306:51
1612.36:316:49
1712.26:326:47
1812.26:336:45
1912.16:356:43
2012.16:366:41
2112.06:376:39
2212.06:386:37
2311.96:396:35
2411.96:406:33
2511.86:426:32
2611.86:436:30
2711.76:446:28
2811.76:456:26
2911.66:466:24
3011.66:486:22

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 5.47 kWh/m².

For context, solar energy here swings from a low near 1.64 kWh/m² to a high of 8.02 kWh/m² in July across the year — September's 5.47 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
16.3Intense
26.3Intense
36.2Intense
46.2Intense
56.1Intense
66.0Intense
76.0Bright
85.9Bright
95.9Bright
105.8Bright
115.7Bright
125.7Bright
135.6Bright
145.5Bright
155.5Bright
165.4Bright
175.4Bright
185.3Bright
195.3Bright
205.2Bright
215.1Bright
225.1Bright
235.0Bright
245.0Bright
254.9Bright
264.8Bright
274.8Bright
284.7Bright
294.7Bright
304.6Bright
Planning a trip in September

Is September a good time to visit Meridian?

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

7.9
Sightseeing
1st-best month of the year
8.1
Beach & pool
1st-best month of the year

September is one of the better times to visit Meridian for general sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Meridian in September

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

In September, Meridian sees daytime highs around 81°F and nights near 54°F. Pack light clothes. Worth having: sun protection.

light clothessun protection

UV index in Meridian 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 Meridian peaks around July 13 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 14 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJul 13UV 9Dec 14UV 1
UV index (midday)Level
Jan2Low
Feb2Moderate
Mar4Moderate
Apr5High
May8Very high
Jun9Very high
Jul9Very high
Aug7Very high
Sep6High
Oct4Moderate
Nov2Low
Dec1Low

Air quality in Meridian 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 Meridian is worst in August — around 45 µg/m³ PM2.5 (poor), about 6.0× the cleanest month (December, 7 µg/m³).

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

0204060JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateModerateGoodAug 1742 µg/m³Dec 208 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb9Good
Mar10Good
Apr10Good
May10Good
Jun8Good
Jul20Moderate
Aug45Poor
Sep21Moderate
Oct15Moderate
Nov9Good
Dec7Good
Location & terrain

Where is Meridian?

Meridian sits at 43.6°N, 116.4°W, 2,605 ft above sea level, in United States. The nearest listed city is Eagle, 6.2 mi away.

Topography around Meridian

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

Within 2 miles, the terrain around Meridian has only modest variations in elevation — a maximum elevation change of 108 ft around an average of 2,605 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 1,165 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 7,146 ft.

The land around Meridian is covered by artificial surfaces (55%) and trees (22%) within 2 miles, grassland (31%), artificial surfaces (24%) and cropland (22%) within 10 miles, and grassland (65%) within 50 miles.

2 miles
108 ft
10 miles
1,165 ft
50 miles
7,146 ft
treesshrubsgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Eagle 6.2 mi · Kuna 8.7 mi · Boise 9.3 mi · Nampa 9.9 mi · Caldwell 15 mi · Twin Falls 121 mi · Pendleton 185 mi · Lewiston Orchards 193 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 Meridian (43.6121°, -116.3915°, elevation 2,605 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).