Climate and average weather in San Luis Río Colorado

In San Luis Río Colorado, the summers are sweltering, dry, and clear and the winters are mild and mostly clear.

Best: early January to early April

Over the course of the year, the temperature in San Luis Río Colorado typically varies from 9°C to 41°C, and is rarely below 5°C or above 44°C. July is the hottest month of the year, while December is the coldest.

Based on the travel score, the best times of year to visit San Luis Río Colorado for warm-weather activities are from early January to early April and late October to late December.

Hottest
Jul
41°
Coldest
Dec
Wettest
Sep
13 mm
Driest
Jun
1 mm
Rain / yr
85 mm
16 wet days
Daylight
9.9–14.1 h
shortest–longest
Elevation
36 m
32.5°N
Clearest
Jun
10% cloud

San Luis Río Colorado is municipal seat of San Luis, State of Sonora, Mexico.

Founded
1918

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

San Luis Río Colorado weather by month, at a glance

The whole year in one picture — sky, rain, humidity, temperature and travel score. Click any band to jump to its full chart.

Each stripe is one measure across the whole year, stacked so a single day reads top to bottom. The sky band runs overcast grey on top down to clear blue at the base — more blue means sunnier — followed by the rainfall curve, the humidity band, a temperature strip that tints each stretch of the year by how warm its average high is, and the travel-score line at the foot. Scan straight down any date to read that day across every measure at once; the score climbs highest around early January to early April.

Temperature through the year

Average highAverage lowShaded bands: 10–90% of days

Daily average highs and lows in San Luis Río Colorado, from 1991–2020 of climate data. The shaded bands show the range most days fall in — 10th to 90th percentile.

The hot season lasts 4.2 months, from May 27 to September 30, with daily high temperatures above 36°C. The hottest month of the year in San Luis Río Colorado is July, with an average high of 41°C and low of 28°C.

The cool season lasts 3.1 months, from November 23 to February 23, with daily high temperatures below 24°C. The coldest month of the year in San Luis Río Colorado is December, with an average low of 9°C and high of 21°C.

Days typically run about 13°C warmer than nights, with the widest day–night swing (around 15°C) in June.

10°20°30°40°JanFebMarAprMayJunJulAugSepOctNovDec
Avg high (°C)Avg low (°C)
Jan2210
Feb2411
Mar2713
Apr3116
May3520
Jun3924
Jul4128
Aug4129
Sep3825
Oct3319
Nov2613
Dec219

How hot and cold San Luis Río Colorado really feels

Feels-like highFeels-like lowactual air temp

The felt-temperature range through the year — heat index on the day's high (summer humidity), wind chill on the night's low (winter wind). The dashed lines are the plain thermometer; the gap is how much hotter or colder it really feels.

On the hottest afternoons, once humidity is folded in, San Luis Río Colorado feels like about 43°C (around August 15). About 180 days a year carry some heat stress, and 90 of them tip into dangerous heat (feels-like above 39°C), peaking in August.

10°20°30°40°JanFebMarAprMayJunJulAugSepOctNovDecdangerous heat
Feels-like high (°C)Air high (°C)Feels-like low (°C)Air low (°C)
Jan2222810
Feb24241111
Mar27271313
Apr31311616
May35352020
Jun39392424
Jul42412828
Aug43412929
Sep39382525
Oct33331919
Nov26261313
Dec212189

Average hourly temperature in San Luis Río Colorado

A compact picture of the whole year, hour by hour: each column is a day, each row an hour, and the color is the modeled average temperature. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.

Read left to right for the day of the year and top to bottom for the hour of the day; the color is the modeled temperature, cool blues through to hot reds on the same scale as the other charts. A vertical slice is a single day's swing — coolest just before dawn, warmest in the mid-afternoon — while a horizontal slice follows one hour across the seasons. The darker overlay marks night and the lighter one the twilight around sunrise and sunset. Colors run warmest on July afternoons, near 41°C, and coldest before dawn in December, near C.

JanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AM

San Luis Río Colorado weather by month

Every month at a glance. Click a month for its detailed page.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan22° / 10°91.510.18.4
Feb24° / 11°132.310.88.6
Mar27° / 13°101.511.88.1
Apr31° / 16°30.612.86.1
May35° / 20°10.213.63.5
Jun39° / 24°10.214.10.7
Jul41° / 28°51.513.90.0
Aug41° / 29°112.913.20.0
Sep38° / 25°132.212.21.2
Oct33° / 19°50.911.24.9
Nov26° / 13°60.810.38.6
Dec21° / 91.79.98.2

Chance of rain

How likely it is to rain on a typical day, and how that shifts across the wetter and drier seasons.

San Luis Río Colorado gets about 85 mm of precipitation a year. On a typical day the chance of rain is mostly dry, but that rises and falls sharply with the seasons.

The wetter season lasts 2.6 months, from around Jul 9 to Sep 24, peaking in September at about 12% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Jun 15.

September is the wettest month by volume, with 13 mm over about 2 wet days; June is the driest, with 1 mm.

0%10%20%JanFebMarAprMayJunJulAugSepOctNovDecdrierwetterdriermostly drysome rainSep 1 · 12%Jun 15 · 0%
Rain on a day (%)Rain days
Jan52
Feb82
Mar52
Apr21
May10
Jun10
Jul52
Aug93
Sep72
Oct31
Nov31
Dec52

Monthly rainfall

Over a full year, San Luis Río Colorado collects about 85 mm of rain across 16 wet days — roughly 7 mm in an average month.

It doesn’t fall evenly. September is the wettest month with 13 mm, while June is the driest at just 1 mm. The three wettest months alone bring about 44% of the year’s total.

025JanFebMarAprMayJunJulAugSepOctNovDec9131031151113569
Rainfall (mm)Rain days
Jan92
Feb132
Mar102
Apr31
May10
Jun10
Jul52
Aug113
Sep132
Oct51
Nov61
Dec92

Clouds and sunshine

ClearMostly clearPartly cloudyMostly cloudyOvercast

How often the daytime sky is clear, partly cloudy or overcast.

In San Luis Río Colorado, the average share of the sky covered by clouds shows moderate seasonal variation over the course of the year.

The clearer part of the year begins around April 6 and lasts for 7.1 months, ending around November 7. The clearest month is June, when the sky is clear, mostly clear, or partly cloudy 94% of the time on average.

The cloudier part of the year begins around November 8 and lasts for 4.9 months, ending around April 5. The cloudiest month is February, when it is overcast or mostly cloudy 26% of the time.

0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%JanFebMarAprMayJunJulAugSepOctNovDecJun 16 · 95%Feb 16 · 73%clearmostly clearpartly cloudymostly cloudyovercastcloudierclearercloudier
Clearer (%)Cloudier (%)
Jan7525
Feb7426
Mar8020
Apr8812
May9010
Jun946
Jul8812
Aug919
Sep946
Oct919
Nov8218
Dec7525

Daylight, sunrise and sunset

DaylightNight

Hours of daylight through the year, with sunrise and sunset times.

The gold band is daylight — sunrise runs along its lower edge, sunset along the upper — so it widens toward summer and pinches toward winter, with night the dark area above and below. The longest day, around June 8, brings about 14 h 06 min of light; the shortest, around January 1, only 9 h 54 min — a swing of roughly 4 h 12 min.

12 AM4 AM8 AM12 PM4 PM8 PM12 AMJanFebMarAprMayJunJulAugSepOctNovDec
Daylight (h)Sunrise (AM)Sunset (PM)
Jan10.17:465:51
Feb10.87:296:18
Mar11.86:566:41
Apr12.86:157:03
May13.65:467:25
Jun14.15:367:43
Jul13.95:477:43
Aug13.26:077:19
Sep12.26:286:39
Oct11.26:496:00
Nov10.37:155:34
Dec9.97:395:32

Sunny days

How many genuinely sunny days each month brings — days the sky stays clear or mostly clear — banded into plain-language zones.

San Luis Río Colorado averages about 23 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 17 and 28 days.

The sunnier stretch runs 3.5 months, from around Apr 8 to Jul 22. The sunniest month is June, with roughly 27 sunny days (brilliant).

The greyest month is February, down near 18 sunny days — about 33% fewer than the June peak.

051015202530JanFebMarAprMayJunJulAugSepOctNovDecgreyersunniergreyergloomymixedbrightbrilliantJun 1728 daysFeb 1917 days
Sunny daysSky
Jan19Bright
Feb17Bright
Mar21Bright
Apr23Brilliant
May26Brilliant
Jun27Brilliant
Jul25Brilliant
Aug25Brilliant
Sep26Brilliant
Oct26Brilliant
Nov22Bright
Dec20Bright

Humidity comfort

DryComfortableHumidMuggyOppressiveMiserable

Share of days at each humidity comfort level, based on the dew point — the measure that tracks how muggy it actually feels.

Humidity comfort is graded by the dew point — the temperature at which the air would be fully saturated — because it tracks how muggy it actually feels far better than relative humidity does. A low dew point feels dry and crisp; a high one feels sticky and oppressive no matter the reading on a humidity gauge.

In San Luis Río Colorado, how humid it feels changes dramatically over the year.

The more humid part of the year lasts 3.4 months, from around June 24 to October 6. The muggiest month is August, when the air feels humid, muggy or worse about 72% of the time.

The most comfortable stretch runs from around October 7 to June 23, and January is the most comfortable month — the air is dry or comfortable 100% of the time.

0%10%20%30%40%50%60%70%80%90%100%JanFebMarAprMayJunJulAugSepOctNovDecJan 12 · 100%Aug 22 · 25%oppressivemuggyhumiddrycomfortablecomfortablehumidcomfortable
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
Jan9910000
Feb9910000
Mar10000000
Apr10000000
May9630000
Jun78137200
Jul2719272260
Aug15132232161
Sep41141519111
Oct80106310
Nov9820000
Dec10000000

Wind

Average wind speed through the year, banded into plain-language speed zones so a number reads as 'breezy' or 'calm' without knowing the scale.

This is the average sustained wind speed at the standard 10 metres above open ground — the steady flow a weather station reports, not the sharper gusts that come and go, which can run half again as fast. It's the number that says whether a place is generally breezy or calm.

Wind in San Luis Río Colorado is steady company: average speeds sit near 10 km/hcalm — in every month of the year, with no meaningful windy or calm season.

051015JanFebMarAprMayJunJulAugSepOctNovDeccalmlight breezeJul 25 · 11 km/hSep 22 · 9 km/h
Wind speed (km/h)Feels
Jan10calm
Feb10calm
Mar10calm
Apr11calm
May10calm
Jun10calm
Jul11calm
Aug10calm
Sep9calm
Oct9calm
Nov9calm
Dec10calm

Best time to visit San Luis Río Colorado

TravelBeach/poolTemperatureCloudsPrecipitation

To characterize how pleasant the weather is in San Luis Río Colorado throughout the year, we compute two travel scores — one for general sightseeing, one for beach and pool weather.

Around late March, San Luis Río Colorado is still near the tail of its best-weather window — great conditions with the peak-season crowds already thinning.

Inferred from the travel-score curve; month-by-month visitor numbers are a planned addition.

The travel score favors clear, rainless days with daytime highs between 18°C and 28°C. Based on this score, the best time of year to visit San Luis Río Colorado for general outdoor tourist activities is from late October to early April, with a peak score in the third week of November.

0246810JanFebMarAprMayJunJulAugSepOctNovDecbest timebest timetravel scoretemperaturecloudsprecipitationNov 21 · 8.9

The travel score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

Travel score (0–10)Rating
Jan8.4ideal
Feb8.6ideal
Mar8.1ideal
Apr6.1good
May3.5poor
Jun0.8poor
Jul0.0poor
Aug0.0poor
Sep1.2poor
Oct5.0fair
Nov8.5ideal
Dec8.2ideal

The beach/pool score favors clear, rainless days with daytime highs between 24°C and 34°C. Based on this score, the best times of year to visit San Luis Río Colorado for hot-weather activities run from late February to mid May and again from early October to late November, with a peak score in the first week of April.

024681012JanFebMarAprMayJunJulAugSepOctNovDecbest timebest timebeach/pool scoretemperaturecloudsprecipitationApr 5 · 9.0

The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

What to pack for San Luis Río Colorado, by month

EssentialRecommendedOptional

Month by month, what's worth putting in the bag — from the temperature range, rain chance, sun and wind. Tap a month for a quick packing note.

For a warm-season trip around July (highs near 41°C), the essentials are light clothes and sun protection. In the cold season around December (highs near 21°C), pack a light layer.

Light clothing
Warm layer
Winter coat
Rain gear
Sun protection
Windbreaker

In July, San Luis Río Colorado sees daytime highs around 41°C and nights near 28°C. Pack light clothes and sun protection.

UV index (midday) in San Luis Río Colorado by month

LowModerateHighVery highExtreme

Clear-sky midday UV index through the year, shaded by the WHO exposure levels — how much sun protection each month calls for.

Under clear skies, the midday UV index in San Luis Río Colorado peaks around June 23 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 18 at about 3 (moderate).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateVery highExtremeVery highHighModerateJun 23UV 11Dec 18UV 3
UV index (midday)Level
Jan4Moderate
Feb5Moderate
Mar5Moderate
Apr8Very high
May8Very high
Jun11Extreme
Jul11Extreme
Aug10Very high
Sep9Very high
Oct6High
Nov4Moderate
Dec3Moderate

Average hourly UV index in San Luis Río Colorado

LowModerateHighVery highExtreme

Modeled clear-sky UV for every hour of every day — when in the day sun protection actually matters.

The whole year hour by hour: each column is a day, each row an hour, and the color is the modeled clear-sky UV index — the midday peak scaled down as the sun sits lower in the sky. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.

UV falls off far faster than brightness as the sun drops, so even in June the burn window is concentrated in the middle of the day: about 8.5 hours a day reach index 3 (protection recommended), and 6 hours reach 6 or more. Mornings and late afternoons stay comparatively gentle year round.

JanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AM
UV ≥ 3 (h/day)UV ≥ 6 (h/day)
Jan3.50
Feb4.50
Mar50
Apr74
May7.54.5
Jun8.56
Jul8.56
Aug85.5
Sep74.5
Oct5.51.5
Nov40
Dec1.50
Almanac & agriculture

Growing season

Chance of a frost-free dayFrost-free year round

San Luis Río Colorado is frost-free year round — even the coldest nights rarely reach freezing, so there is no start or end to the growing season.

0%25%50%75%100%JanFebMarAprMayJunJulAugSepOctNovDecfrost-free year round
Frost-free chance (%)Frost nights
Jan1000
Feb1000
Mar1000
Apr1000
May1000
Jun1000
Jul1000
Aug1000
Sep1000
Oct1000
Nov1000
Dec1000

Growing degree days

Degree days (base 10°C)Frost-free shaded

Growing degree days tally heat above 10°C: each day adds however many degrees its average temperature runs over that threshold, and cold days add nothing. San Luis Río Colorado banks about 5,396 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around August.

02,0004,000JanFebMarAprMayJunJulAugSepOctNovDec
Growing degree days (°C·days)
Jan173
Feb204
Mar319
Apr403
May538
Jun647
Jul765
Aug768
Sep655
Oct492
Nov282
Dec150

Solar energy

Average daily shortwave solar energy reaching the ground, banded into brightness zones so the number means something at a glance.

Solar energy is how much sunlight actually reaches the ground each day, measured in kilowatt-hours per square metre (kWh/m²) — the combined effect of how long the sun is up, how high it climbs, and how much cloud gets in the way. It's the raw fuel a solar panel has to work with: for scale, 1 kWh/m² a day is dim and wintry, while 7+ is desert-bright.

San Luis Río Colorado receives about 6.1 kWh/m² a day of solar energy on average — intense — with a clear seasonal swing between 3.3 and 8.5 kWh/m².

The brighter stretch of the year lasts 6.4 months, from around Mar 14 to Sep 23. The brightest month is June, averaging about 8.4 kWh/m² (intense).

The dimmest month is December, down near 3.4 kWh/m² — roughly 60% less than the June peak.

012345678910JanFebMarAprMayJunJulAugSepOctNovDecdimmerbrighterdimmerdimmoderatebrightintenseJun 118.5 kWhDec 173.3 kWh
Solar energy (kWh/m²)Level
Jan3.7Moderate
Feb4.7Bright
Mar6.2Intense
Apr7.5Intense
May8.3Intense
Jun8.5Intense
Jul7.8Intense
Aug7.1Intense
Sep6.3Intense
Oct5.2Bright
Nov4.0Moderate
Dec3.4Moderate

Where is San Luis Río Colorado?

San Luis Río Colorado sits at 32.5°N, 114.8°W, 36 m above sea level, in Mexico. The nearest listed city is San Luis, 4.0 km away.

Topography around San Luis Río Colorado

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of San Luis Río Colorado.

Within 3 km, the terrain around San Luis Río Colorado has only modest variations in elevation — a maximum elevation change of 24 m around an average of 44 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 53 m; within 80 km, large variations in elevation — a maximum elevation change of 1,108 m.

The land around San Luis Río Colorado is covered by artificial surfaces (83%) within 3 km, bare terrain (56%) and cropland (32%) within 16 km, and bare terrain (73%) within 80 km.

3 km
24 m
16 km
53 m
80 km
1,108 m
treesshrubscroplandartificial surfacesbare terrainwaterwetland
Nearby: San Luis 4.0 km · Somerton 17 km · Yuma 33 km · Ciudad Guadalupe Victoria 36 km · Fortuna Foothills 40 km · Puebla 56 km · Mexicali 67 km · Calexico 73 km

Mexico travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type A / B
120 / 127 V · 60 Hz
Prices
≈ 54% of US
price level, 2025
GDP per capita
$13,889
2025
Happiness
7.0 / 10
World Happiness, 2025
Safe drinking water
43%
of population, 2024
Homicide rate
24.9
per 100k, 2023
Road deaths
12.8
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
Very low
EF EPI 440
Religion
Catholic 78%no religion 11%other Evangelical Churches 8%Jehovah Witness 1%

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 San Luis Río Colorado (32.4555°, -114.7704°, elevation 36 m), 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).