Frankfort weather in August

In August, Frankfort sees average daytime highs of 81°F and overnight lows near 64°F, with 3.8 in of rain across 10.8 wet days and about 13.7 hours of daylight. It is the 2nd-warmest and 5th-wettest month of the year here.

Day-to-day highs hold fairly steady near 81°F through the month. The sky is clear or mostly clear about 37% of the time in August, and the air most often feels humid.

Daylight stretches from about 14 h 18 min at the start of August to 13 hours by month's end. Set against the rest of the year, August is Frankfort's 2nd-clearest and 12th-windiest month. For the whole year in context, see Frankfort's year-round climate.

Daytime high
81°
2nd warmest
Overnight low
64°
11th coldest
Rainfall
3.8 in
10.8 wet days
Daylight
13 h 42 min
5:05 AM – 6:46 PM
Cloud cover
54%
2nd clearest
Wind
6 mph
12th windiest
Solar energy
5.65 kWh/m²
Travel score
6.5
out of 10

Frankfort is village on border of Cook and Will Counties in Illinois, United States of America.

Founded
1879

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in August

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 81°F through the month.

A typical August day in Frankfort 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, August runs about 2°F cooler than July and about 6°F warmer than September.

50°60°70°80°90°151015202531
Avg high (°F)Avg low (°F)
18265
28265
38265
48265
58265
68265
78264
88264
98164
108164
118164
128164
138164
148164
158164
168164
178164
188164
198163
208163
218163
228163
238163
248063
258063
268063
278062
288062
298062
308062
318062

How August really feels in Frankfort

Once humidity and wind are folded in, August 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

August sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Frankfort weather by month

How August compares with the rest of the year at a glance. August is the 2nd-warmest and 5th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan32° / 19°2.38.75.79.30.0
Feb36° / 21°2.07.14.810.30.0
Mar47° / 31°2.910.6311.71.5
Apr59° / 41°4.412.60.913.14.3
May70° / 51°4.612.6014.36.0
Jun79° / 62°4.311.6014.96.3
Jul83° / 66°3.911.9014.75.8
Aug81° / 64°3.810.8013.76.5
Sep75° / 56°3.08.5012.37.1
Oct62° / 44°3.29.50.110.95.4
Nov48° / 34°2.78.61.29.71.9
Dec37° / 24°2.283.99.10.0

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 37% of the time in August.

Beyond those clear spells, partly cloudy skies cover about 20% of August, with mostly cloudy or overcast conditions the remaining 44%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15446
25545
35545
45545
55545
65545
75644
85644
95545
105545
115545
125644
135644
145644
155644
165743
175743
185743
195644
205644
215644
225644
235545
245644
255644
265743
275743
285842
295941
305941
315941

Chance of precipitation in August

Any precipitation

Frankfort gets around 3.8 in of rain over 10.8 wet days in August. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 34% and peaks near 35% on the wettest days.

0%10%20%30%40%50%151015202531
Rain chance (%)
134
234
334
434
534
634
734
834
935
1035
1135
1235
1335
1435
1535
1635
1735
1835
1935
2035
2135
2235
2335
2434
2533
2633
2732
2832
2931
3031
3131

Humidity in August

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, August lands in the humid band about 26% of days. Sticky, muggy-or-worse air turns up on roughly 38% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
19232726151
29232725151
39242725151
49242724151
59242724151
69242724151
79242724151
810252723151
910252723151
1011252623151
1111252623141
1211252623141
1312252623141
1412242623131
1512242624131
1612242624131
1713242624131
1813232625121
1913232625121
2013232626121
2113222626121
2213222626121
2313222626121
2413222626111
2514232626111
2614232526111
2715232525111
2816242525100
2917242525100
301824252490
311925242390

Wind in August

Winds average 6 mph in August, the calmest month.

Across August, daily wind ranges from about 6 mph on the calmest days to 7 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (mph)Feels
16calm
26calm
36calm
46calm
56calm
66calm
76calm
86calm
96calm
106calm
116calm
126calm
136calm
146calm
156calm
166calm
176calm
186calm
196calm
206calm
216calm
226calm
236calm
246calm
256calm
267calm
277calm
287calm
297calm
307calm
317calm

Sunrise & sunset in August

DaylightNight

Daylight runs from about 14 h 18 min at the start of August to 13 hours by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 78 minutes over August. Sunrise moves from 4:50 AM to 5:21 AM, and sunset from 7:05 PM to 6:22 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.34:507:05
214.24:517:04
314.24:527:03
414.24:537:02
514.14:547:01
614.14:556:59
714.04:566:58
814.04:576:57
914.04:586:56
1013.94:596:54
1113.95:006:53
1213.85:016:52
1313.85:026:50
1413.85:036:49
1513.75:046:47
1613.75:056:46
1713.65:066:44
1813.65:076:43
1913.65:086:41
2013.55:096:40
2113.55:106:38
2213.45:116:37
2313.45:126:35
2413.35:136:34
2513.35:146:32
2613.25:166:30
2713.25:176:29
2813.25:186:27
2913.15:196:25
3013.15:206:24
3113.05:216:22

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 5.65 kWh/m².

For context, solar energy here swings from a low near 1.66 kWh/m² to a high of 6.5 kWh/m² in June across the year — August's 5.65 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
16.1Intense
26.1Intense
36.1Intense
46.0Intense
56.0Intense
66.0Bright
75.9Bright
85.9Bright
95.9Bright
105.8Bright
115.8Bright
125.8Bright
135.7Bright
145.7Bright
155.7Bright
165.6Bright
175.6Bright
185.6Bright
195.5Bright
205.5Bright
215.5Bright
225.5Bright
235.4Bright
245.4Bright
255.4Bright
265.3Bright
275.3Bright
285.3Bright
295.3Bright
305.2Bright
315.2Bright
Planning a trip in August

Is August a good time to visit Frankfort?

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

6.5
Sightseeing
2nd-best month of the year
6.7
Beach & pool
1st-best month of the year

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

What to pack for Frankfort in August

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

In August, Frankfort sees daytime highs around 81°F and nights near 64°F. Pack light clothes. Worth having: rain gear and sun protection. About 11 days see rain.

light clothesrain gearsun protection

Sea temperature near Frankfort in August

The nearest coast averages about 73°F in August — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 26 mi away) is warmest in August at about 73°F and coldest in February near 35°F.

It's comfortable for a long swim from Jul 10 to Sep 16 — about 2.3 months when the water holds above 68°F.

30°40°50°60°70°80°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmcomfortable to swim
Sea temperature (°F)Comfort
Jan38Bracing
Feb35Bracing
Mar35Bracing
Apr39Bracing
May46Bracing
Jun59Cool
Jul70Refreshing
Aug73Refreshing
Sep68Refreshing
Oct58Bracing
Nov49Bracing
Dec42Bracing

UV index in Frankfort in August

LowModerateHighVery highExtreme

Clear-sky midday UV in August 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 Frankfort peaks around June 22 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 at about 2 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJun 22UV 9Dec 21UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May7Very high
Jun9Very high
Jul9Very high
Aug8Very high
Sep6High
Oct3Moderate
Nov2Moderate
Dec2Low

Air quality in Frankfort in August

GoodModeratePoorUnhealthyVery unhealthy

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

Air quality in Frankfort is worst in July — around 18 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (October, 8 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1418 µg/m³Oct 238 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb14Moderate
Mar15Moderate
Apr15Moderate
May17Moderate
Jun17Moderate
Jul18Moderate
Aug16Moderate
Sep12Moderate
Oct8Good
Nov9Good
Dec10Good
Location & terrain

Where is Frankfort?

Frankfort sits at 41.5°N, 87.8°W, 761 ft above sea level, in United States. The nearest listed city is Mokena, 3.1 mi away.

Topography around Frankfort

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

Within 2 miles, the terrain around Frankfort has only modest variations in elevation — a maximum elevation change of 131 ft around an average of 745 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 269 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 741 ft.

The land around Frankfort is covered by trees (33%), grassland (23%) and cropland (22%) within 2 miles, cropland (33%), trees (24%) and grassland (23%) within 10 miles, and cropland (47%) within 50 miles.

2 miles
131 ft
10 miles
269 ft
50 miles
741 ft
treesgrasslandcroplandartificial surfaceswater
August weather nearby: Mokena 3.1 mi · New Lenox 6.2 mi · Tinley Park 6.2 mi · Matteson 6.8 mi · Country Club Hills 8.1 mi · Homer Glen 8.7 mi · Park Forest 9.3 mi · Oak Forest 9.3 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 Frankfort (41.4959°, -87.8487°, elevation 761 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. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. 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).