Rapid City weather in August

In August, Rapid City sees average daytime highs of 81°F and overnight lows near 56°F, with 2.4 in of rain across 10.9 wet days and about 13.8 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 51% of the time in August, and the air most often feels dry.

Daylight stretches from about 14 h 30 min at the start of August to 13 h 06 min by month's end. Set against the rest of the year, August is Rapid City's 2nd-clearest and 11th-windiest month. For the whole year in context, see Rapid City's year-round climate.

Daytime high: 81°; 2nd warmest
Overnight low: 56°; 11th coldest
Rainfall: 2.4 in; 10.9 wet days
Daylight: 13 h 48 min; 5:02 AM – 6:52 PM
Cloud cover: 43%; 2nd clearest
Wind: 7 mph; 11th windiest
Solar energy: 6.14 kWh/m²
Travel score: 6.7; out of 10

Rapid City is seat of Pennington County, South Dakota, United States.

Density: 521/km²; people per km²
Founded: 1876

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

← July Rapid City year-round climate September →Best places to visit in August

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

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 Rapid City reaches about 81°F in the afternoon and slips back to 56°F overnight — a 24°F spread between the day's warmth and the night's chill. On most days the high lands between 71°F and 91°F. Set against its neighbours, August runs on par with July and about 9°F warmer than September.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Avg high (°F)	82	82	82	82	82	82	82	82	81	81	81	81	81	81	81	81	81	81	81	81	81	81	81	81	80	80	80	80	80	79	79
Avg low (°F)	58	58	58	58	58	58	58	58	57	57	57	57	57	57	57	56	56	56	56	56	56	56	56	56	55	55	55	55	55	54	54

	Avg high (°F)	Avg low (°F)
1	82	58
2	82	58
3	82	58
4	82	58
5	82	58
6	82	58
7	82	58
8	82	58
9	81	57
10	81	57
11	81	57
12	81	57
13	81	57
14	81	57
15	81	57
16	81	56
17	81	56
18	81	56
19	81	56
20	81	56
21	81	56
22	81	56
23	81	56
24	81	56
25	80	55
26	80	55
27	80	55
28	80	55
29	80	55
30	79	54
31	79	54

How August really feels in Rapid City

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

heat index over the day's high

Days feeling ≤ 32°F

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.

Rapid City 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.

Month	High / Low (°F)	Rainfall (inches)	Wet days	Snow days	Daylight (hours)	Travel score
Jan	36° / 17°	0.5	3.9	3.9	9.1	0.0
Feb	38° / 18°	0.7	5	5.1	10.2	0.0
Mar	46° / 25°	1.6	7.6	5.4	11.6	1.4
Apr	54° / 32°	3.2	11.8	5.5	13.2	3.1
May	64° / 42°	4.4	14.1	1.2	14.5	5.0
Jun	74° / 52°	3.8	14.5	0.1	15.2	6.1
Jul	82° / 58°	3.1	13.4	0	15	5.9
Aug	81° / 56°	2.4	10.9	0	13.8	6.7
Sep	72° / 47°	1.6	6.7	0.4	12.3	7.4
Oct	58° / 36°	2.0	7.3	2.7	10.8	4.7
Nov	46° / 25°	0.8	4.4	3.8	9.4	1.3
Dec	37° / 18°	0.6	3.6	3.9	8.8	0.0

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 51% of the time in August.

Beyond those clear spells, partly cloudy skies cover about 21% of August, with mostly cloudy or overcast conditions the remaining 27%. Skies tend to open up as the month goes on.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Clearer (%)	70	71	71	71	71	71	72	72	72	72	73	73	73	73	73	73	73	72	73	73	73	73	73	73	73	73	74	74	74	74	75
Cloudier (%)	30	29	29	29	29	29	28	28	28	28	27	27	27	27	27	27	27	28	27	27	27	27	27	27	27	27	26	26	26	26	25

	Clearer (%)	Cloudier (%)
1	70	30
2	71	29
3	71	29
4	71	29
5	71	29
6	71	29
7	72	28
8	72	28
9	72	28
10	72	28
11	73	27
12	73	27
13	73	27
14	73	27
15	73	27
16	73	27
17	73	27
18	72	28
19	73	27
20	73	27
21	73	27
22	73	27
23	73	27
24	73	27
25	73	27
26	73	27
27	74	26
28	74	26
29	74	26
30	74	26
31	75	25

Chance of precipitation in August

Any precipitation

Rapid City gets around 2.4 in of rain over 10.9 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 44% on the wettest days. The odds ease toward the end of the month.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Rain chance (%)	44	44	44	44	44	44	43	43	42	41	40	38	37	36	35	33	32	31	31	30	29	28	28	27	27	26	26	25	25	25	24

	Rain chance (%)
1	44
2	44
3	44
4	44
5	44
6	44
7	43
8	43
9	42
10	41
11	40
12	38
13	37
14	36
15	35
16	33
17	32
18	31
19	31
20	30
21	29
22	28
23	28
24	27
25	27
26	26
27	26
28	25
29	25
30	25
31	24

Humidity in August

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, August lands in the dry band about 68% of days. It rarely turns muggy — the humid and sticky bands barely register.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Dry (%)	50	50	51	52	52	53	54	56	57	59	61	64	65	68	69	71	72	73	74	75	76	77	78	78	79	79	80	81	82	83	84
Comfortable (%)	37	37	37	36	36	36	35	34	33	32	31	29	28	26	25	24	23	22	21	20	19	18	17	17	16	16	15	15	14	13	13
Humid (%)	13	13	12	12	12	11	11	10	10	9	8	7	7	6	6	5	5	5	5	5	5	5	5	5	5	5	5	4	4	4	3

	Dry (%)	Comfortable (%)	Humid (%)
1	50	37	13
2	50	37	13
3	51	37	12
4	52	36	12
5	52	36	12
6	53	36	11
7	54	35	11
8	56	34	10
9	57	33	10
10	59	32	9
11	61	31	8
12	64	29	7
13	65	28	7
14	68	26	6
15	69	25	6
16	71	24	5
17	72	23	5
18	73	22	5
19	74	21	5
20	75	20	5
21	76	19	5
22	77	18	5
23	78	17	5
24	78	17	5
25	79	16	5
26	79	16	5
27	80	15	5
28	81	15	4
29	82	14	4
30	83	13	4
31	84	13	3

Wind in August

Winds average 7 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.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Wind speed (mph)	6	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7
Feels	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm

	Wind speed (mph)	Feels
1	6	calm
2	7	calm
3	7	calm
4	7	calm
5	7	calm
6	7	calm
7	7	calm
8	7	calm
9	7	calm
10	7	calm
11	7	calm
12	7	calm
13	7	calm
14	7	calm
15	7	calm
16	7	calm
17	7	calm
18	7	calm
19	7	calm
20	7	calm
21	7	calm
22	7	calm
23	7	calm
24	7	calm
25	7	calm
26	7	calm
27	7	calm
28	7	calm
29	7	calm
30	7	calm
31	7	calm

Sunrise & sunset in August

DaylightNight

Daylight runs from about 14 h 30 min at the start of August to 13 h 06 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 84 minutes over August. Sunrise moves from 4:45 AM to 5:19 AM, and sunset from 7:13 PM to 6:27 PM.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Daylight (h)	14.5	14.4	14.4	14.4	14.3	14.3	14.2	14.2	14.2	14.1	14.1	14.0	14.0	13.9	13.9	13.8	13.8	13.8	13.7	13.7	13.6	13.6	13.5	13.5	13.4	13.4	13.3	13.3	13.2	13.2	13.1
Sunrise (AM)	4:45	4:46	4:47	4:48	4:49	4:50	4:51	4:52	4:54	4:55	4:56	4:57	4:58	4:59	5:01	5:02	5:03	5:04	5:05	5:06	5:08	5:09	5:10	5:11	5:12	5:13	5:15	5:16	5:17	5:18	5:19
Sunset (PM)	7:13	7:12	7:11	7:10	7:08	7:07	7:06	7:04	7:03	7:01	7:00	6:58	6:57	6:55	6:54	6:52	6:51	6:49	6:47	6:46	6:44	6:42	6:41	6:39	6:37	6:36	6:34	6:32	6:30	6:28	6:27

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	14.5	4:45	7:13
2	14.4	4:46	7:12
3	14.4	4:47	7:11
4	14.4	4:48	7:10
5	14.3	4:49	7:08
6	14.3	4:50	7:07
7	14.2	4:51	7:06
8	14.2	4:52	7:04
9	14.2	4:54	7:03
10	14.1	4:55	7:01
11	14.1	4:56	7:00
12	14.0	4:57	6:58
13	14.0	4:58	6:57
14	13.9	4:59	6:55
15	13.9	5:01	6:54
16	13.8	5:02	6:52
17	13.8	5:03	6:51
18	13.8	5:04	6:49
19	13.7	5:05	6:47
20	13.7	5:06	6:46
21	13.6	5:08	6:44
22	13.6	5:09	6:42
23	13.5	5:10	6:41
24	13.5	5:11	6:39
25	13.4	5:12	6:37
26	13.4	5:13	6:36
27	13.3	5:15	6:34
28	13.3	5:16	6:32
29	13.2	5:17	6:30
30	13.2	5:18	6:28
31	13.1	5:19	6:27

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 6.14 kWh/m².

For context, solar energy here swings from a low near 1.91 kWh/m² to a high of 6.88 kWh/m² in July across the year — August's 6.14 kWh/m² sits near the top of that range.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Solar energy (kWh/m²)	6.5	6.5	6.5	6.4	6.4	6.4	6.4	6.3	6.3	6.3	6.3	6.3	6.2	6.2	6.2	6.2	6.1	6.1	6.1	6.1	6.0	6.0	6.0	5.9	5.9	5.9	5.8	5.8	5.7	5.7	5.7
Level	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright

	Solar energy (kWh/m²)	Level
1	6.5	Intense
2	6.5	Intense
3	6.5	Intense
4	6.4	Intense
5	6.4	Intense
6	6.4	Intense
7	6.4	Intense
8	6.3	Intense
9	6.3	Intense
10	6.3	Intense
11	6.3	Intense
12	6.3	Intense
13	6.2	Intense
14	6.2	Intense
15	6.2	Intense
16	6.2	Intense
17	6.1	Intense
18	6.1	Intense
19	6.1	Intense
20	6.1	Intense
21	6.0	Intense
22	6.0	Intense
23	6.0	Bright
24	5.9	Bright
25	5.9	Bright
26	5.9	Bright
27	5.8	Bright
28	5.8	Bright
29	5.7	Bright
30	5.7	Bright
31	5.7	Bright

Planning a trip in August

Hazard calendar for Rapid City

In seasonPeak

In August, Rapid City sits inside its rainy season season. The full year is below, with each hazard's peak months called out.

Rapid City's rainy season runs April–August, when most of the year's rain falls.

Rainy season

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Is August a good time to visit Rapid City?

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

6.7

Sightseeing

2nd-best month of the year

6.8

Beach & pool

1st-best month of the year

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

What to pack for Rapid City in August

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

In August, Rapid City sees daytime highs around 81°F and nights near 56°F. Pack light clothes and sun protection. Worth having: rain gear. About 11 days see rain.

light clothessun protectionrain gear

UV index in Rapid City in August

LowModerateHighVery highExtreme

Clear-sky midday UV in August 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 Rapid City peaks around June 20 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 20 at about 1 (low).

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

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
UV index (midday)	2	3	4	5	7	9	8	6	6	4	2	1
Level	Low	Moderate	Moderate	High	High	Very high	Very high	High	High	Moderate	Low	Low

	UV index (midday)	Level
Jan	2	Low
Feb	3	Moderate
Mar	4	Moderate
Apr	5	High
May	7	High
Jun	9	Very high
Jul	8	Very high
Aug	6	High
Sep	6	High
Oct	4	Moderate
Nov	2	Low
Dec	1	Low

Location & terrain

Where is Rapid City?

Rapid City sits at 44.1°N, 103.2°W, 3,241 ft above sea level, in United States. The nearest listed city is Gillette, 114 mi away.

Topography around Rapid City

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

Within 2 miles, the terrain around Rapid City has only modest variations in elevation — a maximum elevation change of 719 ft around an average of 3,340 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 2,008 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 5,108 ft.

The land around Rapid City is covered by artificial surfaces (49%) and grassland (33%) within 2 miles, grassland (64%) and trees (24%) within 10 miles, and grassland (69%) and trees (22%) within 50 miles.

2 miles

719 ft

artificial surfaces 49%

10 miles

2,008 ft

grassland 64%

50 miles

5,108 ft

grassland 69%

treesgrasslandcroplandartificial surfacesbare terrain

← July Rapid City year-round climate September →Best places to visit in August

August weather nearby: Gillette 114 mi · Casper 176 mi · Sheridan 190 mi · Dickinson 194 mi · Cheyenne 219 mi · Mandan 221 mi · Bismarck 222 mi · Laramie 226 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

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 Rapid City (44.0805°, -103.231°, elevation 3,241 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. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).

	Avg high (°F)	Avg low (°F)
1	82	58
2	82	58
3	82	58
4	82	58
5	82	58
6	82	58
7	82	58
8	82	58
9	81	57
10	81	57
11	81	57
12	81	57
13	81	57
14	81	57
15	81	57
16	81	56
17	81	56
18	81	56
19	81	56
20	81	56
21	81	56
22	81	56
23	81	56
24	81	56
25	80	55
26	80	55
27	80	55
28	80	55
29	80	55
30	79	54
31	79	54

	Clearer (%)	Cloudier (%)
1	70	30
2	71	29
3	71	29
4	71	29
5	71	29
6	71	29
7	72	28
8	72	28
9	72	28
10	72	28
11	73	27
12	73	27
13	73	27
14	73	27
15	73	27
16	73	27
17	73	27
18	72	28
19	73	27
20	73	27
21	73	27
22	73	27
23	73	27
24	73	27
25	73	27
26	73	27
27	74	26
28	74	26
29	74	26
30	74	26
31	75	25

	Rain chance (%)
1	44
2	44
3	44
4	44
5	44
6	44
7	43
8	43
9	42
10	41
11	40
12	38
13	37
14	36
15	35
16	33
17	32
18	31
19	31
20	30
21	29
22	28
23	28
24	27
25	27
26	26
27	26
28	25
29	25
30	25
31	24

	Dry (%)	Comfortable (%)	Humid (%)
1	50	37	13
2	50	37	13
3	51	37	12
4	52	36	12
5	52	36	12
6	53	36	11
7	54	35	11
8	56	34	10
9	57	33	10
10	59	32	9
11	61	31	8
12	64	29	7
13	65	28	7
14	68	26	6
15	69	25	6
16	71	24	5
17	72	23	5
18	73	22	5
19	74	21	5
20	75	20	5
21	76	19	5
22	77	18	5
23	78	17	5
24	78	17	5
25	79	16	5
26	79	16	5
27	80	15	5
28	81	15	4
29	82	14	4
30	83	13	4
31	84	13	3

	Avg high (°F)	Avg low (°F)
1	82	58
2	82	58
3	82	58
4	82	58
5	82	58
6	82	58
7	82	58
8	82	58
9	81	57
10	81	57
11	81	57
12	81	57
13	81	57
14	81	57
15	81	57
16	81	56
17	81	56
18	81	56
19	81	56
20	81	56
21	81	56
22	81	56
23	81	56
24	81	56
25	80	55
26	80	55
27	80	55
28	80	55
29	80	55
30	79	54
31	79	54

	Clearer (%)	Cloudier (%)
1	70	30
2	71	29
3	71	29
4	71	29
5	71	29
6	71	29
7	72	28
8	72	28
9	72	28
10	72	28
11	73	27
12	73	27
13	73	27
14	73	27
15	73	27
16	73	27
17	73	27
18	72	28
19	73	27
20	73	27
21	73	27
22	73	27
23	73	27
24	73	27
25	73	27
26	73	27
27	74	26
28	74	26
29	74	26
30	74	26
31	75	25

	Rain chance (%)
1	44
2	44
3	44
4	44
5	44
6	44
7	43
8	43
9	42
10	41
11	40
12	38
13	37
14	36
15	35
16	33
17	32
18	31
19	31
20	30
21	29
22	28
23	28
24	27
25	27
26	26
27	26
28	25
29	25
30	25
31	24

	Dry (%)	Comfortable (%)	Humid (%)
1	50	37	13
2	50	37	13
3	51	37	12
4	52	36	12
5	52	36	12
6	53	36	11
7	54	35	11
8	56	34	10
9	57	33	10
10	59	32	9
11	61	31	8
12	64	29	7
13	65	28	7
14	68	26	6
15	69	25	6
16	71	24	5
17	72	23	5
18	73	22	5
19	74	21	5
20	75	20	5
21	76	19	5
22	77	18	5
23	78	17	5
24	78	17	5
25	79	16	5
26	79	16	5
27	80	15	5
28	81	15	4
29	82	14	4
30	83	13	4
31	84	13	3

	Avg high (°F)	Avg low (°F)
1	82	58
2	82	58
3	82	58
4	82	58
5	82	58
6	82	58
7	82	58
8	82	58
9	81	57
10	81	57
11	81	57
12	81	57
13	81	57
14	81	57
15	81	57
16	81	56
17	81	56
18	81	56
19	81	56
20	81	56
21	81	56
22	81	56
23	81	56
24	81	56
25	80	55
26	80	55
27	80	55
28	80	55
29	80	55
30	79	54
31	79	54

	Clearer (%)	Cloudier (%)
1	70	30
2	71	29
3	71	29
4	71	29
5	71	29
6	71	29
7	72	28
8	72	28
9	72	28
10	72	28
11	73	27
12	73	27
13	73	27
14	73	27
15	73	27
16	73	27
17	73	27
18	72	28
19	73	27
20	73	27
21	73	27
22	73	27
23	73	27
24	73	27
25	73	27
26	73	27
27	74	26
28	74	26
29	74	26
30	74	26
31	75	25

	Rain chance (%)
1	44
2	44
3	44
4	44
5	44
6	44
7	43
8	43
9	42
10	41
11	40
12	38
13	37
14	36
15	35
16	33
17	32
18	31
19	31
20	30
21	29
22	28
23	28
24	27
25	27
26	26
27	26
28	25
29	25
30	25
31	24

	Dry (%)	Comfortable (%)	Humid (%)
1	50	37	13
2	50	37	13
3	51	37	12
4	52	36	12
5	52	36	12
6	53	36	11
7	54	35	11
8	56	34	10
9	57	33	10
10	59	32	9
11	61	31	8
12	64	29	7
13	65	28	7
14	68	26	6
15	69	25	6
16	71	24	5
17	72	23	5
18	73	22	5
19	74	21	5
20	75	20	5
21	76	19	5
22	77	18	5
23	78	17	5
24	78	17	5
25	79	16	5
26	79	16	5
27	80	15	5
28	81	15	4
29	82	14	4
30	83	13	4
31	84	13	3