St. Johns weather in August

In August, St. Johns sees average daytime highs of 87°F and overnight lows near 76°F, with 5.7 in of rain across 21.2 wet days and about 13.1 hours of daylight. It is the 2nd-warmest and 1st-wettest month of the year here.

Day-to-day highs hold fairly steady near 87°F through the month. The sky is clear or mostly clear about 21% of the time in August, and the air most often feels oppressive.

Daylight stretches from about 13 h 30 min at the start of August to 12 h 42 min by month's end. Set against the rest of the year, August is St. Johns's 12th-clearest and 11th-windiest month. For the whole year in context, see St. Johns's year-round climate.

Daytime high
87°
2nd warmest
Overnight low
76°
12th coldest
Rainfall
5.7 in
21.2 wet days
Daylight
13 h 06 min
5:57 AM – 7:03 PM
Cloud cover
66%
12th clearest
Wind
6 mph
11th windiest
Solar energy
5.46 kWh/m²
Travel score
3.4
out of 10

St. Johns is unincorporated community in St. Johns County, Florida, United States.

Founded
2005

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 87°F through the month.

A typical August day in St. Johns reaches about 87°F in the afternoon and slips back to 76°F overnight — a 11°F spread between the day's warmth and the night's chill. On most days the high lands between 83°F and 91°F. Set against its neighbours, August runs on par with July and about 3°F warmer than September.

70°80°90°151015202531
Avg high (°F)Avg low (°F)
18876
28876
38876
48876
58876
68876
78876
88876
98876
108876
118876
128876
138876
148876
158876
168776
178776
188776
198776
208776
218776
228776
238776
248776
258776
268776
278776
288776
298676
308676
318676

How August really feels in St. Johns

Once humidity and wind are folded in, August averages 31 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
31
heat index over the day's high
Days feeling ≤ 32°F
0
wind chill below the day's low

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

St. Johns weather by month

How August compares with the rest of the year at a glance. August is the 2nd-warmest and 1st-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysDaylight (hours)Travel score
Jan65° / 49°2.57.710.36.4
Feb67° / 52°2.56.910.96.6
Mar72° / 56°2.87.311.87.2
Apr77° / 62°2.16.712.77.5
May83° / 69°2.58.713.56.3
Jun86° / 74°5.017.613.94.0
Jul88° / 76°4.820.113.73.4
Aug87° / 76°5.721.213.13.4
Sep84° / 74°5.517.212.24.5
Oct79° / 67°3.29.811.36.8
Nov72° / 58°1.76.210.57.4
Dec67° / 53°2.26.710.16.7

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 21% of the time in August, the cloudiest month of the year.

Beyond those clear spells, partly cloudy skies cover about 20% of August, with mostly cloudy or overcast conditions the remaining 59%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
13961
23961
33961
43961
53961
63961
73862
84060
94060
104060
114159
124159
134159
144060
154258
164258
174258
184258
194258
204357
214357
224357
234357
244258
254159
264159
274159
284159
294159
304060
314060

Chance of precipitation in August

Any precipitation

St. Johns gets around 5.7 in of rain over 21.2 wet days in August, the wettest month. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 68% and peaks near 69% on the wettest days.

0%20%40%60%80%151015202531
Rain chance (%)
169
269
369
469
569
669
769
869
969
1068
1168
1268
1369
1469
1569
1669
1769
1869
1969
2069
2168
2268
2368
2467
2567
2667
2766
2866
2966
3065
3165

Humidity in August

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, August lands in the oppressive band about 58% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202531
Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1016435
2016336
3016237
4026038
5025939
6025840
7025741
8025741
9025642
10025543
11025543
12025543
13025543
14025543
15025543
16025543
17025642
18025642
19025741
20025741
21035740
22035839
23035839
24035938
25045937
26046036
27046135
28156133
29156232
30166231
31166429

Wind in August

Winds average 6 mph in August.

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
266calm
276calm
286calm
297calm
307calm
317calm

Sunrise & sunset in August

DaylightNight

Daylight runs from about 13 h 30 min at the start of August to 12 h 42 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 48 minutes over August. Sunrise moves from 5:48 AM to 6:06 AM, and sunset from 7:16 PM to 6:46 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.55:487:16
213.45:497:16
313.45:497:15
413.45:507:14
513.45:517:13
613.45:517:12
713.35:527:12
813.35:537:11
913.35:537:10
1013.35:547:09
1113.25:547:08
1213.25:557:07
1313.25:567:06
1413.15:567:05
1513.15:577:04
1613.15:577:03
1713.15:587:02
1813.05:597:01
1913.05:597:00
2013.06:006:59
2113.06:006:58
2212.96:016:57
2312.96:026:56
2412.96:026:55
2512.86:036:53
2612.86:036:52
2712.86:046:51
2812.86:046:50
2912.76:056:49
3012.76:066:47
3112.76:066:46

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 5.46 kWh/m².

For context, solar energy here swings from a low near 2.83 kWh/m² to a high of 6.44 kWh/m² in May across the year — August's 5.46 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
15.8Bright
25.8Bright
35.7Bright
45.7Bright
55.7Bright
65.7Bright
75.7Bright
85.7Bright
95.6Bright
105.6Bright
115.6Bright
125.6Bright
135.6Bright
145.5Bright
155.5Bright
165.5Bright
175.5Bright
185.5Bright
195.4Bright
205.4Bright
215.4Bright
225.4Bright
235.3Bright
245.3Bright
255.3Bright
265.3Bright
275.2Bright
285.2Bright
295.2Bright
305.1Bright
315.1Bright
Planning a trip in August

Hazard calendar for St. Johns

In seasonPeak

In August, St. Johns sits inside its atlantic hurricane and rainy season season. The full year is below, with each hazard's peak months called out.

St. Johns sits in the Atlantic hurricane belt; the season peaks August–October.

St. Johns's rainy season runs June–October, when most of the year's rain falls.

Atlantic hurricane
Rainy season
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is August a good time to visit St. Johns?

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

3.4
Sightseeing
11th-best month of the year
5.0
Beach & pool
9th-best month of the year

August is a weaker month for outdoor sightseeing in St. Johns.

What to pack for St. Johns in August

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

In August, St. Johns sees daytime highs around 87°F and nights near 76°F. Pack light clothes and rain gear. Worth having: sun protection. About 21 days see rain.

light clothesrain gearsun protection

Sea temperature near St. Johns in August

The nearest coast averages about 82°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 23 mi away) is warmest in August at about 82°F and coldest in February near 61°F.

It's comfortable for a long swim from Apr 13 to Nov 28 — about 7.6 months when the water holds above 68°F.

60°70°80°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°F)Comfort
Jan62Cool
Feb61Cool
Mar63Cool
Apr69Refreshing
May75Refreshing
Jun80Warm
Jul82Warm
Aug82Tropical
Sep82Warm
Oct78Warm
Nov70Refreshing
Dec65Cool

UV index in St. Johns in August

LowModerateHighVery highExtreme

Clear-sky midday UV in August peaks around 10 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in St. Johns peaks around June 21 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 19 at about 4 (moderate).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highExtremeVery highHighModerateJun 21UV 11Dec 19UV 4
UV index (midday)Level
Jan4Moderate
Feb6High
Mar7Very high
Apr7High
May9Very high
Jun11Extreme
Jul10Extreme
Aug10Very high
Sep8Very high
Oct6High
Nov5Moderate
Dec4Moderate

Air quality in St. Johns 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 St. Johns is worst in July — around 18 µg/m³ PM2.5 (moderate), about 2.4× the cleanest month (December, 7 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1618 µg/m³Dec 138 µg/m³
PM2.5 (µg/m³)Level
Jan9Good
Feb13Moderate
Mar12Moderate
Apr13Moderate
May14Moderate
Jun16Moderate
Jul18Moderate
Aug16Moderate
Sep12Good
Oct8Good
Nov8Good
Dec7Good
Location & terrain

Where is St. Johns?

St. Johns sits at 30.1°N, 81.5°W, 33 ft above sea level, in United States. The nearest listed city is Fruit Cove, 6.2 mi away.

Topography around St. Johns

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

Within 2 miles, the terrain around St. Johns has only modest variations in elevation — a maximum elevation change of 118 ft around an average of 39 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 144 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 308 ft.

The land around St. Johns is covered by trees (65%) within 2 miles, trees (62%) within 10 miles, and trees (59%) and water (28%) within 50 miles.

2 miles
118 ft
10 miles
144 ft
50 miles
308 ft
treesgrasslandcroplandartificial surfaceswaterwetland
August weather nearby: Fruit Cove 6.2 mi · Fleming Island 11 mi · Palm Valley 12 mi · Lakeside 14 mi · Ponte Vedra Beach 15 mi · Jacksonville Beach 17 mi · Oakleaf Plantation 18 mi · Jacksonville 19 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 St. Johns (30.0815°, -81.5477°, elevation 33 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. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). 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).