Arnold in Summer

In summer (June, July and August), Arnold sees average daytime highs around 86°F and overnight lows near 68°F, with 10.4 in of rain over about 31 wet days across the season. It is the warmest season of the year and the 2nd-wettest season.

Over the season highs climb from about 81°F in early June to 85°F by late August. The sky is clear or mostly clear about 37% of the time across summer, and the air most often feels muggy.

Summer is Arnold's 3rd-best season to visit on our travel score. For the whole year in context, see Arnold's year-round climate.

Avg daytime high
86°F
warmest season of the year
Avg overnight low
68°F
Rainfall
10.4 in
31 wet days
Avg wind
5 mph
Travel score
5.0
3rd-best season
Months
Jun · Jul · Aug

Temperature in Arnold in Summer

Average highAverage lowShaded bands: 10–90% of days

Over the season highs climb from about 81°F in early June to 85°F by late August.

A typical summer day in Arnold reaches about 86°F and drops to 68°F overnight. The warmest of the three months is July, the coolest June.

60°80°100°JunJulAug

How summer really feels in Arnold

Once humidity and wind are folded in, summer brings about 30 days that feel above 90°F and 0 that feel at or below 32°F.

Days feeling ≥ 90°F
30
heat index over the day's high
Days feeling ≤ 32°F
0
wind chill below the day's low

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

Arnold weather by month

How the three summer months (June, July and August) 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 Summer

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 37% of the time across summer.

0%25%50%75%100%JunJulAug

Chance of precipitation in Summer

Any precipitation

Arnold gets around 10.4 in of rain over 31 wet days across summer. The line is the day-by-day chance of measurable precipitation.

0%10%20%30%40%50%JunJulAug

Humidity in Summer

DryComfortableHumidMuggyOppressiveMiserable

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

0%25%50%75%100%JunJulAug

Wind in Summer

Winds average 5 mph across summer.

0246810JunJulAug

Sunrise & sunset in Summer

DaylightNight

Daylight runs from about 14 h 30 min in early June to 12 h 54 min by late August. The lit band spans sunrise to sunset each day.

12 AM4 AM8 AM12 PM4 PM8 PM12 AMJunJulAug

Solar energy in Summer

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day across summer, about 6.2 kWh/m².

0246JunJulAug
Planning a trip in summer

Is summer a good time to visit Arnold?

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

5.0
Sightseeing
3rd-best month of the year
6.8
Beach & pool
1st-best month of the year

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

What to pack for Arnold in Summer

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

In summer, Arnold sees daytime highs around 86°F and nights near 68°F. Pack light clothes and sun protection. Worth having: rain gear. About 31 days see rain.

light clothessun protectionrain gear

UV index in Arnold in Summer

LowModerateHighVery highExtreme

Clear-sky midday UV across summer averages around 9 (very high — sun protection essential). 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 Summer

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where summer 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
Summer 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.