Rialto weather in April

In April, Rialto sees average daytime highs of 69°F and overnight lows near 48°F, with 1.1 in of precipitation across 3.9 wet days and about 12.8 hours of daylight. It is the 7th-warmest and 5th-wettest month of the year here.

Highs climb over the month, from about 66°F in the first days to 72°F by the end. The sky is clear or mostly clear about 58% of the time in April, and the air most often feels dry.

Daylight stretches from about 12 h 18 min at the start of April to 13 h 18 min by month's end. Set against the rest of the year, April is Rialto's 8th-clearest and 3rd-windiest month. For the whole year in context, see Rialto's year-round climate.

Daytime high: 69°; 7th warmest
Overnight low: 48°; 6th coldest
Precipitation: 1.1 in; 3.9 wet days
Daylight: 12 h 54 min; 5:24 AM – 6:15 PM
Cloud cover: 36%; 8th clearest
Wind: 4 mph; 3rd windiest
Solar energy: 6.77 kWh/m²
Travel score: 7.7; out of 10

Rialto is city in San Bernardino County, California, United States.

Density: 1,780/km²; people per km²
Founded: 1911

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

← March Rialto year-round climate May →Best places to visit in April

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

Temperature in April

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 66°F in the first days to 72°F by the end.

A typical April day in Rialto reaches about 69°F in the afternoon and slips back to 48°F overnight — a 21°F spread between the day's warmth and the night's chill. On most days the high lands between 56°F and 81°F. Set against its neighbours, April runs about 5°F warmer than March and about 6°F cooler than May.

	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
Avg high (°F)	65	66	66	66	66	66	66	67	67	67	67	67	68	68	68	69	69	69	69	70	70	70	71	71	71	71	72	72	72	72
Avg low (°F)	46	46	46	46	46	46	46	46	46	47	47	47	47	47	47	47	48	48	48	48	49	49	49	49	50	50	50	50	51	51

	Avg high (°F)	Avg low (°F)
1	65	46
2	66	46
3	66	46
4	66	46
5	66	46
6	66	46
7	66	46
8	67	46
9	67	46
10	67	47
11	67	47
12	67	47
13	68	47
14	68	47
15	68	47
16	69	47
17	69	48
18	69	48
19	69	48
20	70	48
21	70	49
22	70	49
23	71	49
24	71	49
25	71	50
26	71	50
27	72	50
28	72	50
29	72	51
30	72	51

Rialto weather by month

How April compares with the rest of the year at a glance. April is the 7th-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	60° / 41°	2.9	6.1	0.6	10	5.5
Feb	61° / 42°	3.6	6.8	1.1	10.7	5.5
Mar	64° / 45°	2.2	6.2	0.8	11.7	6.6
Apr	69° / 48°	1.1	3.9	0.3	12.8	7.7
May	74° / 53°	0.5	2.6	0	13.7	8.6
Jun	82° / 59°	0.1	0.7	0	14.2	8.2
Jul	87° / 65°	0.5	2.6	0	14	6.0
Aug	89° / 66°	0.4	2.8	0	13.3	5.5
Sep	85° / 62°	0.3	1.8	0	12.2	7.0
Oct	77° / 54°	0.7	2.4	0	11.1	8.7
Nov	67° / 46°	1.0	3.1	0.2	10.2	7.7
Dec	60° / 41°	2.2	5	0.4	9.8	5.6

Cloud cover in April

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 58% of the time in April.

Beyond those clear spells, partly cloudy skies cover about 14% of April, 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
Clearer (%)	68	69	69	69	70	70	70	70	71	71	71	72	72	72	73	73	73	74	74	74	74	75	76	76	76	76	76	76	76	76
Cloudier (%)	32	31	31	31	30	30	30	30	29	29	29	28	28	28	27	27	27	26	26	26	26	25	24	24	24	24	24	24	24	24

	Clearer (%)	Cloudier (%)
1	68	32
2	69	31
3	69	31
4	69	31
5	70	30
6	70	30
7	70	30
8	70	30
9	71	29
10	71	29
11	71	29
12	72	28
13	72	28
14	72	28
15	73	27
16	73	27
17	73	27
18	74	26
19	74	26
20	74	26
21	74	26
22	75	25
23	76	24
24	76	24
25	76	24
26	76	24
27	76	24
28	76	24
29	76	24
30	76	24

Chance of precipitation in April

Any precipitationSnow

Rialto gets around 1.1 in of rain and snow over 3.9 wet days in April. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 13% and peaks near 16% on the wettest days, and about 0 day brings 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
Rain chance (%)	16	16	16	15	15	15	15	14	14	14	13	13	13	12	12	12	12	12	12	11	11	11	11	11	11	11	11	11	11	11
Snow chance (%)	2	2	2	2	2	2	2	2	2	2	1	1	1	1	1	1	1	1	1	1	1	0	0	0	0	0	0	0	0	0

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

Humidity in April

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, April 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
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
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

	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

Wind in April

Winds average 4 mph in April.

Across April, daily wind ranges from about 4 mph on the calmest days to 4 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
Wind speed (mph)	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4
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

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

Sunrise & sunset in April

DaylightNight

Daylight runs from about 12 h 18 min at the start of April to 13 h 18 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 60 minutes over April. Sunrise moves from 5:45 AM to 5:07 AM, and sunset from 6:04 PM to 6:26 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
Daylight (h)	12.3	12.4	12.4	12.4	12.5	12.5	12.5	12.6	12.6	12.6	12.7	12.7	12.7	12.8	12.8	12.9	12.9	12.9	13.0	13.0	13.0	13.1	13.1	13.1	13.2	13.2	13.2	13.3	13.3	13.3
Sunrise (AM)	5:45	5:43	5:42	5:40	5:39	5:38	5:36	5:35	5:34	5:32	5:31	5:29	5:28	5:27	5:25	5:24	5:23	5:22	5:20	5:19	5:18	5:17	5:15	5:14	5:13	5:12	5:11	5:10	5:09	5:07
Sunset (PM)	6:04	6:04	6:05	6:06	6:07	6:08	6:08	6:09	6:10	6:11	6:11	6:12	6:13	6:14	6:14	6:15	6:16	6:17	6:18	6:18	6:19	6:20	6:21	6:21	6:22	6:23	6:24	6:25	6:25	6:26

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	12.3	5:45	6:04
2	12.4	5:43	6:04
3	12.4	5:42	6:05
4	12.4	5:40	6:06
5	12.5	5:39	6:07
6	12.5	5:38	6:08
7	12.5	5:36	6:08
8	12.6	5:35	6:09
9	12.6	5:34	6:10
10	12.6	5:32	6:11
11	12.7	5:31	6:11
12	12.7	5:29	6:12
13	12.7	5:28	6:13
14	12.8	5:27	6:14
15	12.8	5:25	6:14
16	12.9	5:24	6:15
17	12.9	5:23	6:16
18	12.9	5:22	6:17
19	13.0	5:20	6:18
20	13.0	5:19	6:18
21	13.0	5:18	6:19
22	13.1	5:17	6:20
23	13.1	5:15	6:21
24	13.1	5:14	6:21
25	13.2	5:13	6:22
26	13.2	5:12	6:23
27	13.2	5:11	6:24
28	13.3	5:10	6:25
29	13.3	5:09	6:25
30	13.3	5:07	6:26

Solar energy in April

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in April, about 6.77 kWh/m².

For context, solar energy here swings from a low near 3.02 kWh/m² to a high of 8.25 kWh/m² in June across the year — April's 6.77 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
Solar energy (kWh/m²)	6.2	6.2	6.3	6.3	6.3	6.4	6.4	6.5	6.5	6.6	6.6	6.7	6.7	6.7	6.8	6.8	6.8	6.9	6.9	7.0	7.0	7.0	7.1	7.1	7.1	7.1	7.2	7.2	7.2	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

	Solar energy (kWh/m²)	Level
1	6.2	Intense
2	6.2	Intense
3	6.3	Intense
4	6.3	Intense
5	6.3	Intense
6	6.4	Intense
7	6.4	Intense
8	6.5	Intense
9	6.5	Intense
10	6.6	Intense
11	6.6	Intense
12	6.7	Intense
13	6.7	Intense
14	6.7	Intense
15	6.8	Intense
16	6.8	Intense
17	6.8	Intense
18	6.9	Intense
19	6.9	Intense
20	7.0	Intense
21	7.0	Intense
22	7.0	Intense
23	7.1	Intense
24	7.1	Intense
25	7.1	Intense
26	7.1	Intense
27	7.2	Intense
28	7.2	Intense
29	7.2	Intense
30	7.2	Intense

Planning a trip in April

Is April a good time to visit Rialto?

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

7.7

Sightseeing

4th-best month of the year

4.3

Beach & pool

7th-best month of the year

April is one of the better times to visit Rialto for general sightseeing.

What to pack for Rialto in April

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

In April, Rialto sees daytime highs around 69°F and nights near 48°F. Pack sun protection. About 4 days see rain.

sun protection

UV index in Rialto in April

LowModerateHighVery highExtreme

Clear-sky midday UV in April 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 Rialto peaks around June 23 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 16 at about 3 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 11 months of the year.

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
UV index (midday)	4	5	5	8	8	11	11	11	8	6	4	3
Level	Moderate	Moderate	High	Very high	Very high	Extreme	Extreme	Extreme	Very high	High	Moderate	Moderate

	UV index (midday)	Level
Jan	4	Moderate
Feb	5	Moderate
Mar	5	High
Apr	8	Very high
May	8	Very high
Jun	11	Extreme
Jul	11	Extreme
Aug	11	Extreme
Sep	8	Very high
Oct	6	High
Nov	4	Moderate
Dec	3	Moderate

Air quality in Rialto in April

GoodModeratePoorUnhealthyVery unhealthy

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

Air quality in Rialto is worst in September — around 40 µg/m³ PM2.5 (poor), about 5.4× the cleanest month (December, 7 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)	8	9	11	10	8	19	12	20	40	10	8	7
Level	Good	Good	Good	Good	Good	Moderate	Moderate	Moderate	Poor	Good	Good	Good

	PM2.5 (µg/m³)	Level
Jan	8	Good
Feb	9	Good
Mar	11	Good
Apr	10	Good
May	8	Good
Jun	19	Moderate
Jul	12	Moderate
Aug	20	Moderate
Sep	40	Poor
Oct	10	Good
Nov	8	Good
Dec	7	Good

Location & terrain

Where is Rialto?

Rialto sits at 34.1°N, 117.4°W, 1,257 ft above sea level, in United States. The nearest listed city is Bloomington, 3.1 mi away.

Topography around Rialto

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

Within 2 miles, the terrain around Rialto has only modest variations in elevation — a maximum elevation change of 335 ft around an average of 1,250 ft above sea level; within 10 miles, very significant variations in elevation — a maximum elevation change of 4,675 ft; within 50 miles, extreme variations in elevation — a maximum elevation change of 11,417 ft.

The land around Rialto is covered by artificial surfaces (82%) within 2 miles, artificial surfaces (50%) within 10 miles, and shrubs (27%) and artificial surfaces (20%) within 50 miles.

2 miles

335 ft

artificial surfaces 82%

10 miles

4,675 ft

artificial surfaces 50%

50 miles

11,417 ft

shrubs 27%

treesshrubsgrasslandcroplandartificial surfacesbare terrainwater

← March Rialto year-round climate May →Best places to visit in April

April weather nearby: Bloomington 3.1 mi · Fontana 3.7 mi · Colton 3.7 mi · San Bernardino 4.3 mi · Loma Linda 7.5 mi · Rubidoux 8.1 mi · Glen Avon 9.3 mi · Highland 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

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 Rialto (34.1064°, -117.3703°, elevation 1,257 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	65	46
2	66	46
3	66	46
4	66	46
5	66	46
6	66	46
7	66	46
8	67	46
9	67	46
10	67	47
11	67	47
12	67	47
13	68	47
14	68	47
15	68	47
16	69	47
17	69	48
18	69	48
19	69	48
20	70	48
21	70	49
22	70	49
23	71	49
24	71	49
25	71	50
26	71	50
27	72	50
28	72	50
29	72	51
30	72	51

	Clearer (%)	Cloudier (%)
1	68	32
2	69	31
3	69	31
4	69	31
5	70	30
6	70	30
7	70	30
8	70	30
9	71	29
10	71	29
11	71	29
12	72	28
13	72	28
14	72	28
15	73	27
16	73	27
17	73	27
18	74	26
19	74	26
20	74	26
21	74	26
22	75	25
23	76	24
24	76	24
25	76	24
26	76	24
27	76	24
28	76	24
29	76	24
30	76	24

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

	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

	Avg high (°F)	Avg low (°F)
1	65	46
2	66	46
3	66	46
4	66	46
5	66	46
6	66	46
7	66	46
8	67	46
9	67	46
10	67	47
11	67	47
12	67	47
13	68	47
14	68	47
15	68	47
16	69	47
17	69	48
18	69	48
19	69	48
20	70	48
21	70	49
22	70	49
23	71	49
24	71	49
25	71	50
26	71	50
27	72	50
28	72	50
29	72	51
30	72	51

	Clearer (%)	Cloudier (%)
1	68	32
2	69	31
3	69	31
4	69	31
5	70	30
6	70	30
7	70	30
8	70	30
9	71	29
10	71	29
11	71	29
12	72	28
13	72	28
14	72	28
15	73	27
16	73	27
17	73	27
18	74	26
19	74	26
20	74	26
21	74	26
22	75	25
23	76	24
24	76	24
25	76	24
26	76	24
27	76	24
28	76	24
29	76	24
30	76	24

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

	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

	Avg high (°F)	Avg low (°F)
1	65	46
2	66	46
3	66	46
4	66	46
5	66	46
6	66	46
7	66	46
8	67	46
9	67	46
10	67	47
11	67	47
12	67	47
13	68	47
14	68	47
15	68	47
16	69	47
17	69	48
18	69	48
19	69	48
20	70	48
21	70	49
22	70	49
23	71	49
24	71	49
25	71	50
26	71	50
27	72	50
28	72	50
29	72	51
30	72	51

	Clearer (%)	Cloudier (%)
1	68	32
2	69	31
3	69	31
4	69	31
5	70	30
6	70	30
7	70	30
8	70	30
9	71	29
10	71	29
11	71	29
12	72	28
13	72	28
14	72	28
15	73	27
16	73	27
17	73	27
18	74	26
19	74	26
20	74	26
21	74	26
22	75	25
23	76	24
24	76	24
25	76	24
26	76	24
27	76	24
28	76	24
29	76	24
30	76	24

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

	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