Arnold in Fall

In fall (September, October and November), Arnold sees average daytime highs around 67°F and overnight lows near 48°F, with 10.3 in of precipitation over about 24 wet days across the season. It is the 2nd-warmest season and the 3rd-wettest season.

Over the season highs ease from about 84°F in early September to 50°F by late November. The sky is clear or mostly clear about 44% of the time across fall, and the air most often feels dry.

Fall is Arnold's best season of the year to visit on our travel score. For the whole year in context, see Arnold's year-round climate.

Avg daytime high
67°F
2nd-warmest season
Avg overnight low
48°F
Precipitation
10.3 in
24 wet days
Avg wind
7 mph
Travel score
5.8
best season of the year
Months
Sep · Oct · Nov

Temperature in Arnold in Fall

Average highAverage lowShaded bands: 10–90% of days

Over the season highs ease from about 84°F in early September to 50°F by late November.

A typical fall day in Arnold reaches about 67°F and drops to 48°F overnight. The warmest of the three months is September, the coolest November.

20°40°60°80°SepOctNov

How fall really feels in Arnold

Once humidity and wind are folded in, fall brings about 0 days that feel above 90°F and 16 that feel at or below 32°F.

Days feeling ≥ 90°F
0
heat index over the day's high
Days feeling ≤ 32°F
16
wind chill below the day's low

The story in fall is cold — wind chill drags the overnight "feels like" below the raw low.

Arnold weather by month

How the three fall months (September, October and November) compare with the rest of the year — the season's months are highlighted.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan40° / 25°2.88.12.89.60.0
Feb45° / 28°2.57.72.810.51.0
Mar56° / 37°3.810.81.411.73.6
Apr67° / 47°4.611.30.2135.9
May75° / 58°4.913.3014.16.3
Jun84° / 67°4.011.2014.65.4
Jul88° / 70°3.410.2014.44.5
Aug86° / 68°3.09.4013.55.0
Sep80° / 60°3.27.8012.37.0
Oct68° / 48°3.58.10116.7
Nov55° / 38°3.68.30.79.93.6
Dec44° / 29°2.68.22.29.40.8

Cloud cover in Fall

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 44% of the time across fall.

0%25%50%75%100%SepOctNov

Chance of precipitation in Fall

Any precipitationSnow

Arnold gets around 10.3 in of rain and snow over 24 wet days across fall. The line is the day-by-day chance of measurable precipitation.

0%10%20%30%40%SepOctNov

Humidity in Fall

DryComfortableHumidMuggyOppressiveMiserable

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

0%25%50%75%100%SepOctNov

Wind in Fall

Winds average 7 mph across fall.

0246810SepOctNov

Sunrise & sunset in Fall

DaylightNight

Daylight runs from about 12 h 54 min in early September to 9 h 30 min by late November. The lit band spans sunrise to sunset each day.

12 AM4 AM8 AM12 PM4 PM8 PM12 AMSepOctNov

Solar energy in Fall

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day across fall, about 3.5 kWh/m².

0246SepOctNov
Planning a trip in fall

Is fall a good time to visit Arnold?

Our two travel scores rate fall for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.

5.8
Sightseeing
1st-best month of the year
3.5
Beach & pool
2nd-best month of the year

fall is a reasonable time to visit Arnold for sightseeing.

What to pack for Arnold in Fall

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

In fall, Arnold sees daytime highs around 67°F and nights near 48°F. Worth packing: light clothes, a warm layer, rain gear and sun protection. About 24 days see rain.

light clothesa warm layerrain gearsun protection

UV index in Arnold in Fall

LowModerateHighVery highExtreme

Clear-sky midday UV across fall averages around 5 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Arnold peaks around June 22 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 23 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 highHighModerateJun 22UV 9Dec 23UV 2
UV index (midday)Level
Jan2Moderate
Feb3Moderate
Mar5High
Apr7High
May8Very high
Jun9Very high
Jul9Very high
Aug8Very high
Sep7High
Oct4Moderate
Nov3Moderate
Dec2Low

Air quality in Arnold in Fall

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where fall falls, not just the annual average.

Air quality in Arnold is worst in July — around 17 µg/m³ PM2.5 (moderate), about 2.5× the cleanest month (November, 7 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodGoodModerateGoodJul 1517 µg/m³Nov 127 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb10Good
Mar13Moderate
Apr10Good
May13Moderate
Jun15Moderate
Jul17Moderate
Aug14Moderate
Sep11Good
Oct7Good
Nov7Good
Dec8Good
Location & terrain

Where is Arnold?

Arnold sits at 38.4°N, 90.4°W, 604 ft above sea level, in United States. The nearest listed city is Oakville, 5.0 mi away.

Topography around Arnold

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

Within 2 miles, the terrain around Arnold has only modest variations in elevation — a maximum elevation change of 272 ft around an average of 499 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 771 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 1,473 ft.

The land around Arnold is covered by trees (57%) and artificial surfaces (25%) within 2 miles, trees (57%) within 10 miles, and trees (54%) and cropland (29%) within 50 miles.

2 miles
272 ft
10 miles
771 ft
50 miles
1,473 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
Fall weather nearby: Oakville 5.0 mi · Mehlville 6.2 mi · Concord 6.2 mi · Affton 8.7 mi · Lemay 8.7 mi · Kirkwood 11 mi · Webster Groves 11 mi · Manchester 14 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 Arnold (38.4328°, -90.3776°, elevation 604 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.