Castle Rock weather in May

In May, Castle Rock sees average daytime highs of 65°F and overnight lows near 39°F, with 3.0 in of precipitation across 12.3 wet days and about 14.1 hours of daylight. It is the 5th-warmest and 1st-wettest month of the year here.

Highs climb over the month, from about 60°F in the first days to 70°F by the end. The sky is clear or mostly clear about 27% of the time in May, and the air most often feels dry.

Daylight stretches from about 13 h 36 min at the start of May to 14 h 30 min by month's end. Set against the rest of the year, May is Castle Rock's 12th-clearest and 3rd-windiest month. For the whole year in context, see Castle Rock's year-round climate.

Daytime high: 65°; 5th warmest
Overnight low: 39°; 8th coldest
Precipitation: 3.0 in; 12.3 wet days
Daylight: 14 h 12 min; 4:51 AM – 7:00 PM
Cloud cover: 59%; 12th clearest
Wind: 6 mph; 3rd windiest
Solar energy: 6.87 kWh/m²
Travel score: 5.5; out of 10

Castle Rock is town in and seat of Douglas County, Colorado, United States.

Density: 635/km²; people per km²
Founded: 1874

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

← April Castle Rock year-round climate June →Best places to visit in May

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

Temperature in May

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 60°F in the first days to 70°F by the end.

A typical May day in Castle Rock reaches about 65°F in the afternoon and slips back to 39°F overnight — a 26°F spread between the day's warmth and the night's chill. On most days the high lands between 51°F and 77°F. Set against its neighbours, May runs about 10°F warmer than April and about 11°F cooler than June.

	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)	59	59	60	60	61	61	61	62	62	63	63	64	64	64	65	65	65	66	66	66	67	67	67	68	68	68	69	69	70	70	71
Avg low (°F)	33	33	34	34	35	35	35	36	36	37	37	37	38	38	38	39	39	40	40	40	41	41	41	42	42	42	43	43	43	44	44

	Avg high (°F)	Avg low (°F)
1	59	33
2	59	33
3	60	34
4	60	34
5	61	35
6	61	35
7	61	35
8	62	36
9	62	36
10	63	37
11	63	37
12	64	37
13	64	38
14	64	38
15	65	38
16	65	39
17	65	39
18	66	40
19	66	40
20	66	40
21	67	41
22	67	41
23	67	41
24	68	42
25	68	42
26	68	42
27	69	43
28	69	43
29	70	43
30	70	44
31	71	44

How May really feels in Castle Rock

Once humidity and wind are folded in, May averages 0 days that feel above 90°F and 11 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

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

Castle Rock weather by month

How May compares with the rest of the year at a glance. May is the 5th-warmest and 1st-wettest month here — the current month is highlighted below.

Month	High / Low (°F)	Rainfall (inches)	Wet days	Snow days	Daylight (hours)	Travel score
Jan	39° / 12°	0.6	4.2	4.7	9.5	0.0
Feb	42° / 15°	0.7	5	5.4	10.5	0.3
Mar	49° / 22°	1.7	6.9	5.9	11.7	2.2
Apr	55° / 28°	2.6	9.7	6.1	13	3.5
May	65° / 39°	3.0	12.3	1.7	14.1	5.5
Jun	76° / 48°	2.1	10.2	0.1	14.7	6.8
Jul	81° / 54°	2.5	10.9	0	14.5	6.5
Aug	79° / 52°	2.0	10.1	0	13.5	6.9
Sep	72° / 45°	1.3	6.4	0.5	12.3	7.6
Oct	60° / 32°	1.4	5.5	2.4	11	5.7
Nov	48° / 21°	1.0	4.9	4.9	9.8	2.0
Dec	39° / 12°	0.7	3.9	4.4	9.3	0.0

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 27% of the time in May, the cloudiest month of the year.

Beyond those clear spells, partly cloudy skies cover about 24% of May, with mostly cloudy or overcast conditions the remaining 49%.

	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 (%)	51	51	51	51	51	50	50	50	50	50	50	49	49	49	49	49	49	48	48	49	49	50	50	51	51	53	53	54	55	55	56
Cloudier (%)	49	49	49	49	49	50	50	50	50	50	50	51	51	51	51	51	51	52	52	51	51	50	50	49	49	47	47	46	45	45	44

	Clearer (%)	Cloudier (%)
1	51	49
2	51	49
3	51	49
4	51	49
5	51	49
6	50	50
7	50	50
8	50	50
9	50	50
10	50	50
11	50	50
12	49	51
13	49	51
14	49	51
15	49	51
16	49	51
17	49	51
18	48	52
19	48	52
20	49	51
21	49	51
22	50	50
23	50	50
24	51	49
25	51	49
26	53	47
27	53	47
28	54	46
29	55	45
30	55	45
31	56	44

Chance of precipitation in May

Any precipitationSnow

Castle Rock gets around 3.0 in of rain and snow over 12.3 wet days in May, the wettest month. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 39% and peaks near 42% on the wettest days, and about 2 days bring snow.

	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 (%)	37	37	37	37	37	37	37	37	37	37	37	38	38	39	39	40	40	41	41	41	42	42	42	42	42	42	42	42	41	41	41
Snow chance (%)	15	14	13	13	12	11	10	10	9	8	8	7	7	7	6	6	6	5	4	4	3	3	3	2	2	2	1	1	1	1	1

	Rain chance (%)	Snow chance (%)
1	37	15
2	37	14
3	37	13
4	37	13
5	37	12
6	37	11
7	37	10
8	37	10
9	37	9
10	37	8
11	37	8
12	38	7
13	38	7
14	39	7
15	39	6
16	40	6
17	40	6
18	41	5
19	41	4
20	41	4
21	42	3
22	42	3
23	42	3
24	42	2
25	42	2
26	42	2
27	42	1
28	42	1
29	41	1
30	41	1
31	41	1

Humidity in May

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, May lands in the dry band about 100% 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 (%)	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100

	Dry (%)
1	100
2	100
3	100
4	100
5	100
6	100
7	100
8	100
9	100
10	100
11	100
12	100
13	100
14	100
15	100
16	100
17	100
18	100
19	100
20	100
21	100
22	100
23	100
24	100
25	100
26	100
27	100
28	100
29	100
30	100
31	100

Wind in May

Winds average 6 mph in May.

Across May, daily wind ranges from about 6 mph on the calmest days to 6 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	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6	6
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	6	calm
3	6	calm
4	6	calm
5	6	calm
6	6	calm
7	6	calm
8	6	calm
9	6	calm
10	6	calm
11	6	calm
12	6	calm
13	6	calm
14	6	calm
15	6	calm
16	6	calm
17	6	calm
18	6	calm
19	6	calm
20	6	calm
21	6	calm
22	6	calm
23	6	calm
24	6	calm
25	6	calm
26	6	calm
27	6	calm
28	6	calm
29	6	calm
30	6	calm
31	6	calm

Sunrise & sunset in May

DaylightNight

Daylight runs from about 13 h 36 min at the start of May to 14 h 30 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 54 minutes over May. Sunrise moves from 5:08 AM to 4:41 AM, and sunset from 6:46 PM to 7:13 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)	13.6	13.7	13.7	13.7	13.8	13.8	13.9	13.9	13.9	14.0	14.0	14.0	14.1	14.1	14.1	14.2	14.2	14.2	14.2	14.3	14.3	14.3	14.4	14.4	14.4	14.4	14.5	14.5	14.5	14.5	14.5
Sunrise (AM)	5:08	5:06	5:05	5:04	5:03	5:02	5:00	4:59	4:58	4:57	4:56	4:55	4:54	4:53	4:52	4:51	4:50	4:49	4:48	4:48	4:47	4:46	4:45	4:45	4:44	4:43	4:43	4:42	4:42	4:41	4:41
Sunset (PM)	6:46	6:47	6:48	6:49	6:50	6:51	6:52	6:53	6:54	6:55	6:56	6:56	6:57	6:58	6:59	7:00	7:01	7:02	7:03	7:04	7:05	7:06	7:07	7:07	7:08	7:09	7:10	7:11	7:12	7:12	7:13

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	13.6	5:08	6:46
2	13.7	5:06	6:47
3	13.7	5:05	6:48
4	13.7	5:04	6:49
5	13.8	5:03	6:50
6	13.8	5:02	6:51
7	13.9	5:00	6:52
8	13.9	4:59	6:53
9	13.9	4:58	6:54
10	14.0	4:57	6:55
11	14.0	4:56	6:56
12	14.0	4:55	6:56
13	14.1	4:54	6:57
14	14.1	4:53	6:58
15	14.1	4:52	6:59
16	14.2	4:51	7:00
17	14.2	4:50	7:01
18	14.2	4:49	7:02
19	14.2	4:48	7:03
20	14.3	4:48	7:04
21	14.3	4:47	7:05
22	14.3	4:46	7:06
23	14.4	4:45	7:07
24	14.4	4:45	7:07
25	14.4	4:44	7:08
26	14.4	4:43	7:09
27	14.5	4:43	7:10
28	14.5	4:42	7:11
29	14.5	4:42	7:12
30	14.5	4:41	7:12
31	14.5	4:41	7:13

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 6.87 kWh/m².

For context, solar energy here swings from a low near 2.61 kWh/m² to a high of 7.41 kWh/m² in June across the year — May's 6.87 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)	6.7	6.7	6.7	6.7	6.8	6.8	6.8	6.8	6.8	6.8	6.8	6.8	6.8	6.8	6.9	6.9	6.9	6.9	6.9	6.9	6.9	6.9	6.9	7.0	7.0	7.0	7.0	7.1	7.1	7.1	7.2
Level	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense

	Solar energy (kWh/m²)	Level
1	6.7	Intense
2	6.7	Intense
3	6.7	Intense
4	6.7	Intense
5	6.8	Intense
6	6.8	Intense
7	6.8	Intense
8	6.8	Intense
9	6.8	Intense
10	6.8	Intense
11	6.8	Intense
12	6.8	Intense
13	6.8	Intense
14	6.8	Intense
15	6.9	Intense
16	6.9	Intense
17	6.9	Intense
18	6.9	Intense
19	6.9	Intense
20	6.9	Intense
21	6.9	Intense
22	6.9	Intense
23	6.9	Intense
24	7.0	Intense
25	7.0	Intense
26	7.0	Intense
27	7.0	Intense
28	7.1	Intense
29	7.1	Intense
30	7.1	Intense
31	7.2	Intense

Planning a trip in May

Is May a good time to visit Castle Rock?

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

5.5

Sightseeing

6th-best month of the year

2.1

Beach & pool

5th-best month of the year

May is a reasonable time to visit Castle Rock for sightseeing.

What to pack for Castle Rock in May

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

In May, Castle Rock sees daytime highs around 65°F and nights near 39°F. Pack sun protection. Worth having: a warm layer and rain gear. About 12 days see rain.

sun protectiona warm layerrain gear

UV index in Castle Rock in May

LowModerateHighVery highExtreme

Clear-sky midday UV in May 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 Castle Rock peaks around July 15 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 at about 2 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 10 months of the year.

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
UV index (midday)	3	4	7	7	8	11	11	10	8	6	4	2
Level	Moderate	Moderate	Very high	High	Very high	Extreme	Extreme	Extreme	Very high	High	Moderate	Moderate

	UV index (midday)	Level
Jan	3	Moderate
Feb	4	Moderate
Mar	7	Very high
Apr	7	High
May	8	Very high
Jun	11	Extreme
Jul	11	Extreme
Aug	10	Extreme
Sep	8	Very high
Oct	6	High
Nov	4	Moderate
Dec	2	Moderate

Location & terrain

Where is Castle Rock?

Castle Rock sits at 39.4°N, 104.9°W, 6,224 ft above sea level, in United States. The nearest listed city is Parker, 11 mi away.

Topography around Castle Rock

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

Within 2 miles, the terrain around Castle Rock has only modest variations in elevation — a maximum elevation change of 646 ft around an average of 6,368 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 2,028 ft; within 50 miles, extreme variations in elevation — a maximum elevation change of 9,268 ft.

The land around Castle Rock is covered by grassland (52%) and artificial surfaces (28%) within 2 miles, grassland (74%) within 10 miles, and grassland (55%) and trees (29%) within 50 miles.

2 miles

646 ft

grassland 52%

10 miles

2,028 ft

grassland 74%

50 miles

9,268 ft

grassland 55%

treesgrasslandcroplandartificial surfacesbare terrainwater

← April Castle Rock year-round climate June →Best places to visit in May

May weather nearby: Parker 11 mi · Highlands Ranch 14 mi · Centennial 14 mi · Castlewood 15 mi · Southglenn 16 mi · Greenwood Village 17 mi · Littleton 19 mi · Columbine 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

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 Castle Rock (39.3722°, -104.8561°, elevation 6,224 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	59	33
2	59	33
3	60	34
4	60	34
5	61	35
6	61	35
7	61	35
8	62	36
9	62	36
10	63	37
11	63	37
12	64	37
13	64	38
14	64	38
15	65	38
16	65	39
17	65	39
18	66	40
19	66	40
20	66	40
21	67	41
22	67	41
23	67	41
24	68	42
25	68	42
26	68	42
27	69	43
28	69	43
29	70	43
30	70	44
31	71	44

	Clearer (%)	Cloudier (%)
1	51	49
2	51	49
3	51	49
4	51	49
5	51	49
6	50	50
7	50	50
8	50	50
9	50	50
10	50	50
11	50	50
12	49	51
13	49	51
14	49	51
15	49	51
16	49	51
17	49	51
18	48	52
19	48	52
20	49	51
21	49	51
22	50	50
23	50	50
24	51	49
25	51	49
26	53	47
27	53	47
28	54	46
29	55	45
30	55	45
31	56	44

	Rain chance (%)	Snow chance (%)
1	37	15
2	37	14
3	37	13
4	37	13
5	37	12
6	37	11
7	37	10
8	37	10
9	37	9
10	37	8
11	37	8
12	38	7
13	38	7
14	39	7
15	39	6
16	40	6
17	40	6
18	41	5
19	41	4
20	41	4
21	42	3
22	42	3
23	42	3
24	42	2
25	42	2
26	42	2
27	42	1
28	42	1
29	41	1
30	41	1
31	41	1

	Dry (%)
1	100
2	100
3	100
4	100
5	100
6	100
7	100
8	100
9	100
10	100
11	100
12	100
13	100
14	100
15	100
16	100
17	100
18	100
19	100
20	100
21	100
22	100
23	100
24	100
25	100
26	100
27	100
28	100
29	100
30	100
31	100

	Avg high (°F)	Avg low (°F)
1	59	33
2	59	33
3	60	34
4	60	34
5	61	35
6	61	35
7	61	35
8	62	36
9	62	36
10	63	37
11	63	37
12	64	37
13	64	38
14	64	38
15	65	38
16	65	39
17	65	39
18	66	40
19	66	40
20	66	40
21	67	41
22	67	41
23	67	41
24	68	42
25	68	42
26	68	42
27	69	43
28	69	43
29	70	43
30	70	44
31	71	44

	Clearer (%)	Cloudier (%)
1	51	49
2	51	49
3	51	49
4	51	49
5	51	49
6	50	50
7	50	50
8	50	50
9	50	50
10	50	50
11	50	50
12	49	51
13	49	51
14	49	51
15	49	51
16	49	51
17	49	51
18	48	52
19	48	52
20	49	51
21	49	51
22	50	50
23	50	50
24	51	49
25	51	49
26	53	47
27	53	47
28	54	46
29	55	45
30	55	45
31	56	44

	Rain chance (%)	Snow chance (%)
1	37	15
2	37	14
3	37	13
4	37	13
5	37	12
6	37	11
7	37	10
8	37	10
9	37	9
10	37	8
11	37	8
12	38	7
13	38	7
14	39	7
15	39	6
16	40	6
17	40	6
18	41	5
19	41	4
20	41	4
21	42	3
22	42	3
23	42	3
24	42	2
25	42	2
26	42	2
27	42	1
28	42	1
29	41	1
30	41	1
31	41	1

	Dry (%)
1	100
2	100
3	100
4	100
5	100
6	100
7	100
8	100
9	100
10	100
11	100
12	100
13	100
14	100
15	100
16	100
17	100
18	100
19	100
20	100
21	100
22	100
23	100
24	100
25	100
26	100
27	100
28	100
29	100
30	100
31	100

	Avg high (°F)	Avg low (°F)
1	59	33
2	59	33
3	60	34
4	60	34
5	61	35
6	61	35
7	61	35
8	62	36
9	62	36
10	63	37
11	63	37
12	64	37
13	64	38
14	64	38
15	65	38
16	65	39
17	65	39
18	66	40
19	66	40
20	66	40
21	67	41
22	67	41
23	67	41
24	68	42
25	68	42
26	68	42
27	69	43
28	69	43
29	70	43
30	70	44
31	71	44

	Clearer (%)	Cloudier (%)
1	51	49
2	51	49
3	51	49
4	51	49
5	51	49
6	50	50
7	50	50
8	50	50
9	50	50
10	50	50
11	50	50
12	49	51
13	49	51
14	49	51
15	49	51
16	49	51
17	49	51
18	48	52
19	48	52
20	49	51
21	49	51
22	50	50
23	50	50
24	51	49
25	51	49
26	53	47
27	53	47
28	54	46
29	55	45
30	55	45
31	56	44

	Rain chance (%)	Snow chance (%)
1	37	15
2	37	14
3	37	13
4	37	13
5	37	12
6	37	11
7	37	10
8	37	10
9	37	9
10	37	8
11	37	8
12	38	7
13	38	7
14	39	7
15	39	6
16	40	6
17	40	6
18	41	5
19	41	4
20	41	4
21	42	3
22	42	3
23	42	3
24	42	2
25	42	2
26	42	2
27	42	1
28	42	1
29	41	1
30	41	1
31	41	1

	Dry (%)
1	100
2	100
3	100
4	100
5	100
6	100
7	100
8	100
9	100
10	100
11	100
12	100
13	100
14	100
15	100
16	100
17	100
18	100
19	100
20	100
21	100
22	100
23	100
24	100
25	100
26	100
27	100
28	100
29	100
30	100
31	100