Caldwell weather in May

In May, Caldwell sees average daytime highs of 75°F and overnight lows near 50°F, with 1.0 in of rain across 5.7 wet days and about 14.5 hours of daylight. It is the 5th-warmest and 5th-wettest month of the year here.

Highs climb over the month, from about 71°F in the first days to 78°F by the end. The sky is clear or mostly clear about 37% of the time in May, and the air most often feels dry.

Daylight stretches from about 13 h 54 min at the start of May to 15 hours by month's end. Set against the rest of the year, May is Caldwell's 6th-clearest and 2nd-windiest month. For the whole year in context, see Caldwell's year-round climate.

Daytime high: 75°; 5th warmest
Overnight low: 50°; 8th coldest
Rainfall: 1.0 in; 5.7 wet days
Daylight: 14 h 30 min; 5:28 AM – 7:58 PM
Cloud cover: 53%; 6th clearest
Wind: 6 mph; 2nd windiest
Solar energy: 6.99 kWh/m²
Travel score: 7.6; out of 10

Caldwell is city in and county seat of Canyon County, Idaho, United States.

Density: 898/km²; people per km²
Founded: 1883

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

← April Caldwell 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 71°F in the first days to 78°F by the end.

A typical May day in Caldwell reaches about 75°F in the afternoon and slips back to 50°F overnight — a 25°F spread between the day's warmth and the night's chill. On most days the high lands between 62°F and 88°F. Set against its neighbours, May runs about 9°F warmer than April and about 9°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)	70	71	71	71	72	72	72	73	73	73	74	74	74	74	74	75	75	75	76	76	76	76	77	77	77	78	78	78	78	79	79
Avg low (°F)	45	46	46	46	47	47	47	47	48	48	49	49	49	49	50	50	50	51	51	51	51	52	52	52	52	53	53	53	53	54	54

	Avg high (°F)	Avg low (°F)
1	70	45
2	71	46
3	71	46
4	71	46
5	72	47
6	72	47
7	72	47
8	73	47
9	73	48
10	73	48
11	74	49
12	74	49
13	74	49
14	74	49
15	74	50
16	75	50
17	75	50
18	75	51
19	76	51
20	76	51
21	76	51
22	76	52
23	77	52
24	77	52
25	77	52
26	78	53
27	78	53
28	78	53
29	78	53
30	79	54
31	79	54

How May really feels in Caldwell

Once humidity and wind are folded in, May 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

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

Caldwell weather by month

How May compares with the rest of the year at a glance. May is the 5th-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	41° / 27°	1.5	8.7	3.7	9.1	0.1
Feb	48° / 30°	1.0	7	2.1	10.2	1.7
Mar	58° / 37°	1.2	8	0.5	11.6	4.4
Apr	65° / 42°	1.0	6.2	0.1	13.2	6.4
May	75° / 50°	1.0	5.7	0	14.5	7.6
Jun	83° / 57°	0.5	3.1	0	15.2	6.8
Jul	94° / 64°	0.1	0.7	0	14.9	3.7
Aug	92° / 62°	0.1	0.9	0	13.8	4.3
Sep	81° / 54°	0.4	2	0	12.3	7.7
Oct	66° / 43°	0.7	4	0	10.8	7.1
Nov	50° / 34°	1.1	7.4	1	9.5	2.5
Dec	40° / 27°	1.7	9.3	3.5	8.8	0.1

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

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

Beyond those clear spells, partly cloudy skies cover about 18% of May, with mostly cloudy or overcast conditions the remaining 45%.

	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 (%)	58	59	59	59	59	59	58	57	56	55	54	54	53	52	51	51	51	51	51	51	52	52	53	54	54	55	56	56	56	57	57
Cloudier (%)	42	41	41	41	41	41	42	43	44	45	46	46	47	48	49	49	49	49	49	49	48	48	47	46	46	45	44	44	44	43	43

	Clearer (%)	Cloudier (%)
1	58	42
2	59	41
3	59	41
4	59	41
5	59	41
6	59	41
7	58	42
8	57	43
9	56	44
10	55	45
11	54	46
12	54	46
13	53	47
14	52	48
15	51	49
16	51	49
17	51	49
18	51	49
19	51	49
20	51	49
21	52	48
22	52	48
23	53	47
24	54	46
25	54	46
26	55	45
27	56	44
28	56	44
29	56	44
30	57	43
31	57	43

Chance of precipitation in May

Any precipitation

Caldwell gets around 1.0 in of rain over 5.7 wet days in May. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 18% and peaks near 20% on the wettest days.

	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 (%)	17	17	17	17	17	17	17	17	18	18	19	19	19	19	19	19	19	19	19	19	20	19	19	19	19	18	18	18	18	17	17

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

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	99	99	99
Comfortable (%)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	1	1	1

	Dry (%)	Comfortable (%)
1	100	0
2	100	0
3	100	0
4	100	0
5	100	0
6	100	0
7	100	0
8	100	0
9	100	0
10	100	0
11	100	0
12	100	0
13	100	0
14	100	0
15	100	0
16	100	0
17	100	0
18	100	0
19	100	0
20	100	0
21	100	0
22	100	0
23	100	0
24	100	0
25	100	0
26	100	0
27	100	0
28	100	0
29	99	1
30	99	1
31	99	1

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 54 min at the start of May to 15 hours by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 66 minutes over May. Sunrise moves from 5:47 AM to 5:15 AM, and sunset from 7:41 PM to 8:13 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)	13.9	13.9	14.0	14.0	14.1	14.1	14.2	14.2	14.2	14.3	14.3	14.4	14.4	14.4	14.5	14.5	14.6	14.6	14.6	14.7	14.7	14.7	14.8	14.8	14.8	14.8	14.9	14.9	14.9	15.0	15.0
Sunrise (AM)	5:47	5:45	5:44	5:42	5:41	5:40	5:38	5:37	5:36	5:35	5:33	5:32	5:31	5:30	5:29	5:28	5:26	5:25	5:24	5:23	5:22	5:22	5:21	5:20	5:19	5:18	5:17	5:17	5:16	5:15	5:15
Sunset (PM)	7:41	7:42	7:43	7:45	7:46	7:47	7:48	7:49	7:51	7:52	7:53	7:54	7:55	7:56	7:57	7:58	8:00	8:01	8:02	8:03	8:04	8:05	8:06	8:07	8:08	8:09	8:10	8:11	8:12	8:13	8:13

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	13.9	5:47	7:41
2	13.9	5:45	7:42
3	14.0	5:44	7:43
4	14.0	5:42	7:45
5	14.1	5:41	7:46
6	14.1	5:40	7:47
7	14.2	5:38	7:48
8	14.2	5:37	7:49
9	14.2	5:36	7:51
10	14.3	5:35	7:52
11	14.3	5:33	7:53
12	14.4	5:32	7:54
13	14.4	5:31	7:55
14	14.4	5:30	7:56
15	14.5	5:29	7:57
16	14.5	5:28	7:58
17	14.6	5:26	8:00
18	14.6	5:25	8:01
19	14.6	5:24	8:02
20	14.7	5:23	8:03
21	14.7	5:22	8:04
22	14.7	5:22	8:05
23	14.8	5:21	8:06
24	14.8	5:20	8:07
25	14.8	5:19	8:08
26	14.8	5:18	8:09
27	14.9	5:17	8:10
28	14.9	5:17	8:11
29	14.9	5:16	8:12
30	15.0	5:15	8:13
31	15.0	5:15	8:13

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 6.99 kWh/m².

For context, solar energy here swings from a low near 1.59 kWh/m² to a high of 8.01 kWh/m² in July across the year — May's 6.99 kWh/m² falls in the middle.

	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)	6.6	6.7	6.7	6.7	6.8	6.8	6.8	6.8	6.8	6.8	6.9	6.9	6.9	6.9	6.9	6.9	7.0	7.0	7.0	7.0	7.0	7.1	7.1	7.1	7.2	7.2	7.2	7.2	7.3	7.3	7.3
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	6.6	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	6.9	Intense
12	6.9	Intense
13	6.9	Intense
14	6.9	Intense
15	6.9	Intense
16	6.9	Intense
17	7.0	Intense
18	7.0	Intense
19	7.0	Intense
20	7.0	Intense
21	7.0	Intense
22	7.1	Intense
23	7.1	Intense
24	7.1	Intense
25	7.2	Intense
26	7.2	Intense
27	7.2	Intense
28	7.2	Intense
29	7.3	Intense
30	7.3	Intense
31	7.3	Intense

Planning a trip in May

Is May a good time to visit Caldwell?

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

7.6

Sightseeing

2nd-best month of the year

6.2

Beach & pool

5th-best month of the year

May is one of the better times to visit Caldwell for general sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Caldwell in May

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

In May, Caldwell sees daytime highs around 75°F and nights near 50°F. Pack sun protection. Worth having: light clothes. About 6 days see rain.

sun protectionlight clothes

UV index in Caldwell 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 Caldwell peaks around July 13 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 14 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	2	4	5	8	8	9	7	6	4	2	1
Level	Low	Moderate	Moderate	High	Very high	Very high	Very high	Very high	High	Moderate	Low	Low

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

Air quality in Caldwell in May

GoodModeratePoorUnhealthyVery unhealthy

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

Air quality in Caldwell is worst in August — around 31 µg/m³ PM2.5 (moderate), about 5.0× the cleanest month (December, 6 µg/m³).

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

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
PM2.5 (µg/m³)	7	8	10	9	10	8	15	31	16	11	8	6
Level	Good	Good	Good	Good	Good	Good	Moderate	Moderate	Moderate	Good	Good	Good

	PM2.5 (µg/m³)	Level
Jan	7	Good
Feb	8	Good
Mar	10	Good
Apr	9	Good
May	10	Good
Jun	8	Good
Jul	15	Moderate
Aug	31	Moderate
Sep	16	Moderate
Oct	11	Good
Nov	8	Good
Dec	6	Good

Location & terrain

Where is Caldwell?

Caldwell sits at 43.7°N, 116.7°W, 2,375 ft above sea level, in United States. The nearest listed city is Nampa, 11 mi away.

Topography around Caldwell

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

Within 2 miles, the terrain around Caldwell has only modest variations in elevation — a maximum elevation change of 141 ft around an average of 2,385 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 620 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 6,283 ft.

The land around Caldwell is covered by artificial surfaces (37%) within 2 miles, cropland (48%) and grassland (21%) within 10 miles, and grassland (70%) within 50 miles.

2 miles

141 ft

artificial surfaces 37%

10 miles

620 ft

cropland 48%

50 miles

6,283 ft

grassland 70%

treesshrubsgrasslandcroplandartificial surfacesbare terrainwater

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

May weather nearby: Nampa 11 mi · Meridian 15 mi · Eagle 17 mi · Kuna 18 mi · Boise 24 mi · Twin Falls 135 mi · Pendleton 173 mi · Walla Walla 185 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 Caldwell (43.6629°, -116.6874°, elevation 2,375 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. 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).

	Avg high (°F)	Avg low (°F)
1	70	45
2	71	46
3	71	46
4	71	46
5	72	47
6	72	47
7	72	47
8	73	47
9	73	48
10	73	48
11	74	49
12	74	49
13	74	49
14	74	49
15	74	50
16	75	50
17	75	50
18	75	51
19	76	51
20	76	51
21	76	51
22	76	52
23	77	52
24	77	52
25	77	52
26	78	53
27	78	53
28	78	53
29	78	53
30	79	54
31	79	54

	Clearer (%)	Cloudier (%)
1	58	42
2	59	41
3	59	41
4	59	41
5	59	41
6	59	41
7	58	42
8	57	43
9	56	44
10	55	45
11	54	46
12	54	46
13	53	47
14	52	48
15	51	49
16	51	49
17	51	49
18	51	49
19	51	49
20	51	49
21	52	48
22	52	48
23	53	47
24	54	46
25	54	46
26	55	45
27	56	44
28	56	44
29	56	44
30	57	43
31	57	43

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

	Dry (%)	Comfortable (%)
1	100	0
2	100	0
3	100	0
4	100	0
5	100	0
6	100	0
7	100	0
8	100	0
9	100	0
10	100	0
11	100	0
12	100	0
13	100	0
14	100	0
15	100	0
16	100	0
17	100	0
18	100	0
19	100	0
20	100	0
21	100	0
22	100	0
23	100	0
24	100	0
25	100	0
26	100	0
27	100	0
28	100	0
29	99	1
30	99	1
31	99	1

	Avg high (°F)	Avg low (°F)
1	70	45
2	71	46
3	71	46
4	71	46
5	72	47
6	72	47
7	72	47
8	73	47
9	73	48
10	73	48
11	74	49
12	74	49
13	74	49
14	74	49
15	74	50
16	75	50
17	75	50
18	75	51
19	76	51
20	76	51
21	76	51
22	76	52
23	77	52
24	77	52
25	77	52
26	78	53
27	78	53
28	78	53
29	78	53
30	79	54
31	79	54

	Clearer (%)	Cloudier (%)
1	58	42
2	59	41
3	59	41
4	59	41
5	59	41
6	59	41
7	58	42
8	57	43
9	56	44
10	55	45
11	54	46
12	54	46
13	53	47
14	52	48
15	51	49
16	51	49
17	51	49
18	51	49
19	51	49
20	51	49
21	52	48
22	52	48
23	53	47
24	54	46
25	54	46
26	55	45
27	56	44
28	56	44
29	56	44
30	57	43
31	57	43

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

	Dry (%)	Comfortable (%)
1	100	0
2	100	0
3	100	0
4	100	0
5	100	0
6	100	0
7	100	0
8	100	0
9	100	0
10	100	0
11	100	0
12	100	0
13	100	0
14	100	0
15	100	0
16	100	0
17	100	0
18	100	0
19	100	0
20	100	0
21	100	0
22	100	0
23	100	0
24	100	0
25	100	0
26	100	0
27	100	0
28	100	0
29	99	1
30	99	1
31	99	1

	Avg high (°F)	Avg low (°F)
1	70	45
2	71	46
3	71	46
4	71	46
5	72	47
6	72	47
7	72	47
8	73	47
9	73	48
10	73	48
11	74	49
12	74	49
13	74	49
14	74	49
15	74	50
16	75	50
17	75	50
18	75	51
19	76	51
20	76	51
21	76	51
22	76	52
23	77	52
24	77	52
25	77	52
26	78	53
27	78	53
28	78	53
29	78	53
30	79	54
31	79	54

	Clearer (%)	Cloudier (%)
1	58	42
2	59	41
3	59	41
4	59	41
5	59	41
6	59	41
7	58	42
8	57	43
9	56	44
10	55	45
11	54	46
12	54	46
13	53	47
14	52	48
15	51	49
16	51	49
17	51	49
18	51	49
19	51	49
20	51	49
21	52	48
22	52	48
23	53	47
24	54	46
25	54	46
26	55	45
27	56	44
28	56	44
29	56	44
30	57	43
31	57	43

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

	Dry (%)	Comfortable (%)
1	100	0
2	100	0
3	100	0
4	100	0
5	100	0
6	100	0
7	100	0
8	100	0
9	100	0
10	100	0
11	100	0
12	100	0
13	100	0
14	100	0
15	100	0
16	100	0
17	100	0
18	100	0
19	100	0
20	100	0
21	100	0
22	100	0
23	100	0
24	100	0
25	100	0
26	100	0
27	100	0
28	100	0
29	99	1
30	99	1
31	99	1