Climate and average weather in San Luis

In San Luis, the summers are hot, showery, and mostly clear and the winters are mild and mostly clear.

Best: late July to early December

Over the course of the year, the temperature in San Luis typically varies from 4°C to 29°C, and is rarely below -2°C or above 35°C. January is the hottest month of the year, while July is the coldest.

Based on the travel score, the best times of year to visit San Luis for warm-weather activities are from mid February to mid June and late July to early December.

Hottest
Jan
29°
Coldest
Jul
Wettest
Jan
107 mm
Driest
Jun
8 mm
Rain / yr
665 mm
90 wet days
Daylight
9.8–14.2 h
shortest–longest
Elevation
729 m
33.3°S
Clearest
Aug
33% cloud

San Luis is capital city of the San Luis Province in the Cuyo region of Argentina.

Founded
1594

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

San Luis 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 late July to early December.

Temperature through the year

Average highAverage lowShaded bands: 10–90% of days

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

The hot season lasts 4.0 months, from November 12 to March 14, with daily high temperatures above 26°C. The hottest month of the year in San Luis is January, with an average high of 29°C and low of 18°C.

The cool season lasts 3.0 months, from May 17 to August 14, with daily high temperatures below 18°C. The coldest month of the year in San Luis is July, with an average low of 4°C and high of 16°C.

Days typically run about 11°C warmer than nights year-round.

10°20°30°JanFebMarAprMayJunJulAugSepOctNovDec
Avg high (°C)Avg low (°C)
Jan2918
Feb2817
Mar2615
Apr2211
May188
Jun165
Jul164
Aug186
Sep219
Oct2412
Nov2614
Dec2817

Average hourly temperature in San Luis

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 January afternoons, near 29°C, and coldest before dawn in July, near C.

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

San Luis 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
Jan29° / 18°10713.3145.3
Feb28° / 17°8110.913.26.3
Mar26° / 15°8010.112.37.1
Apr22° / 11°53711.27.4
May18° / 254.210.36.8
Jun16° / 81.99.86.3
Jul16° / 92.1106.1
Aug18° / 152.610.87.4
Sep21° / 304.611.87.6
Oct24° / 12°668.712.87.5
Nov26° / 14°8911.713.76.7
Dec28° / 17°10213.114.25.8

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 gets about 665 mm of precipitation a year. On a typical day the chance of rain is some rain, but that rises and falls sharply with the seasons.

The wetter season lasts 6.1 months, from around Oct 8 to Apr 10, peaking in January at about 45% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Jun 26.

January is the wettest month by volume, with 107 mm over about 13 wet days; June is the driest, with 8 mm.

0%10%20%30%40%50%60%JanFebMarAprMayJunJulAugSepOctNovDecwetterdrierwettermostly drysome rainoften wetvery wetJan 6 · 45%Jun 26 · 6%
Rain on a day (%)Rain days
Jan4313
Feb3911
Mar3310
Apr227
May144
Jun72
Jul72
Aug83
Sep165
Oct289
Nov3912
Dec4213

Monthly rainfall

Over a full year, San Luis collects about 665 mm of rain across 90 wet days — roughly 55 mm in an average month.

It doesn’t fall evenly. January is the wettest month with 107 mm, while June is the driest at just 8 mm. The three wettest months alone bring about 45% of the year’s total.

0255075100125JanFebMarAprMayJunJulAugSepOctNovDec107818053258915306689102
Rainfall (mm)Rain days
Jan10713
Feb8111
Mar8010
Apr537
May254
Jun82
Jul92
Aug153
Sep305
Oct669
Nov8912
Dec10213

Clouds and sunshine

ClearMostly clearPartly cloudyMostly cloudyOvercast

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

In San Luis, 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 November 10 and lasts for 4.0 months, ending around March 11. The clearest month is December, when the sky is clear, mostly clear, or partly cloudy 79% of the time on average.

The cloudier part of the year begins around March 12 and lasts for 3.6 months, ending around June 28. The cloudiest month is May, when it is overcast or mostly cloudy 41% 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%JanFebMarAprMayJunJulAugSepOctNovDecDec 18 · 81%May 20 · 56%clearmostly clearpartly cloudymostly cloudyovercastclearercloudierclearer
Clearer (%)Cloudier (%)
Jan7624
Feb7624
Mar7129
Apr6634
May5941
Jun6832
Jul7525
Aug7624
Sep7228
Oct6931
Nov7426
Dec7921

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 January 1, brings about 14 h 12 min of light; the shortest, around June 11, only 9 h 48 min — a swing of roughly 4 h 24 min.

12 AM4 AM8 AM12 PM4 PM8 PM12 AMJanFebMarAprMayJunJulAugSepOctNovDec
Daylight (h)Sunrise (AM)Sunset (PM)
Jan14.06:358:34
Feb13.27:038:17
Mar12.37:277:43
Apr11.27:507:01
May10.38:136:30
Jun9.88:316:20
Jul10.08:316:31
Aug10.88:076:52
Sep11.87:267:14
Oct12.86:457:36
Nov13.76:188:03
Dec14.26:168:27

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 averages about 16 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 13 and 20 days.

The sunnier stretch runs 3.4 months, from around Jun 19 to Sep 28. The sunniest month is August, with roughly 19 sunny days (bright).

The greyest month is May, down near 13 sunny days — about 32% fewer than the August peak.

0510152025JanFebMarAprMayJunJulAugSepOctNovDecgreyersunniergreyergloomymixedbrightbrilliantAug 1120 daysMay 2013 days
Sunny daysSky
Jan16Bright
Feb15Bright
Mar16Bright
Apr16Bright
May13Mixed
Jun16Bright
Jul18Bright
Aug20Bright
Sep18Bright
Oct16Bright
Nov16Bright
Dec17Bright

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, how humid it feels changes dramatically over the year.

The more humid part of the year lasts 3.9 months, from around December 6 to April 3. The muggiest month is January, when the air feels humid, muggy or worse about 33% of the time.

The most comfortable stretch runs from around April 4 to December 5, and May 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%JanFebMarAprMayJunJulAugSepOctNovDecMay 19 · 100%Jan 7 · 63%humidcomfortabledryhumidcomfortablehumid
Dry (%)Comfortable (%)Humid (%)Muggy (%)
Jan3433267
Feb3632257
Mar4928194
Apr801541
May95500
Jun100000
Jul100000
Aug100000
Sep99100
Oct93710
Nov771940
Dec5428153

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.

Across the year, average wind speed in San Luis is typically calm, near 11 km/h, and varies little with the seasons.

The windier part of the year lasts 5.7 months, from around Aug 9 to Jan 29. The windiest month is October, averaging about 13 km/h (light breeze).

The calmer part of the year runs from around Jan 30 to Aug 8, with May the calmest month at about 9 km/h.

05101520JanFebMarAprMayJunJulAugSepOctNovDecwindiercalmerwindiercalmlight breezeOct 9 · 13 km/hMay 21 · 9 km/h
Wind speed (km/h)Feels
Jan11calm
Feb11calm
Mar10calm
Apr10calm
May9calm
Jun9calm
Jul10calm
Aug11calm
Sep12light breeze
Oct13light breeze
Nov12light breeze
Dec12calm

Hazard calendar for San Luis

In seasonPeak

When the seasonal hazards worth planning around — the rainy season, tropical-cyclone risk and dust haze — are active through the year.

San Luis's rainy season runs October–April, when most of the year's rain falls.

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

Best time to visit San Luis

TravelBeach/poolTemperatureCloudsPrecipitation

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

Around late November, San Luis 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 times of year to visit San Luis for general outdoor tourist activities run from mid February to mid June and again from late July to early December, with a peak score in the third week of September.

0246810JanFebMarAprMayJunJulAugSepOctNovDecbest timebest timetravel scoretemperaturecloudsprecipitationSep 16 · 7.7

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
Jan5.3fair
Feb6.3good
Mar7.1good
Apr7.4good
May6.9good
Jun6.2good
Jul6.2good
Aug7.4good
Sep7.6ideal
Oct7.4good
Nov6.7good
Dec5.8good

The beach/pool score favors clear, rainless days with daytime highs between 24°C and 34°C. Based on this score, the best time of year to visit San Luis for hot-weather activities is from early October to early April, with a peak score in the third week of December.

024681012JanFebMarAprMayJunJulAugSepOctNovDecbest timebest timebeach/pool scoretemperaturecloudsprecipitationDec 20 · 7.0

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, 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 January (highs near 29°C), the essentials are light clothes, rain gear and sun protection. In the cold season around July (highs near 16°C), pack a warm layer.

Light clothing
Warm layer
Winter coat
Rain gear
Sun protection
Windbreaker

In January, San Luis sees daytime highs around 29°C and nights near 18°C. Pack light clothes and sun protection. Worth having: rain gear. About 13 days see rain.

UV index (midday) in San Luis 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 peaks around January 17 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near June 21 at about 3 (moderate).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeModerateHighVery highExtremeJan 17UV 14Jun 21UV 3
UV index (midday)Level
Jan14Extreme
Feb13Extreme
Mar10Extreme
Apr6High
May4Moderate
Jun3Moderate
Jul3Moderate
Aug4Moderate
Sep6High
Oct10Very high
Nov12Extreme
Dec13Extreme

Average hourly UV index in San Luis

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 January the burn window is concentrated in the middle of the day: about 9 hours a day reach index 3 (protection recommended), and 7 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)
Jan97
Feb8.56.5
Mar7.55
Apr5.50
May3.50
Jun10
Jul20
Aug4.50
Sep62
Oct85.5
Nov8.56.5
Dec97
Almanac & agriculture

Growing season

Chance of a frost-free dayReliably frost-free (≥90%)

San Luis is mild enough that a frost-free day stays more likely than not even in midwinter. Nights are reliably above freezing from about August 7 to June 26 (324 days); outside that window a hard frost is an occasional risk.

0%25%50%75%100%JanFebMarAprMayJunJulAugSepOctNovDecreliably frost-freereliably frost-freeAug 790%Jun 2690%
Frost-free chance (%)Frost nights
Jan1000
Feb1000
Mar1000
Apr1000
May980
Jun936
Jul8531
Aug9211
Sep970
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 banks about 2,533 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around January.

01,0002,000JanFebMarAprMayJunJulAugSepOctNovDec
Growing degree days (°C·days)
Jan417
Feb346
Mar321
Apr199
May96
Jun14
Jul1
Aug64
Sep141
Oct237
Nov307
Dec389

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 receives about 5.2 kWh/m² a day of solar energy on average — bright — with a clear seasonal swing between 2.7 and 7.6 kWh/m².

The brighter stretch of the year lasts 6.0 months, from around Sep 14 to Mar 16. The brightest month is December, averaging about 7.5 kWh/m² (intense).

The dimmest month is June, down near 2.8 kWh/m² — roughly 63% less than the December peak.

0123456789JanFebMarAprMayJunJulAugSepOctNovDecbrighterdimmerbrighterdimmoderatebrightintenseDec 207.6 kWhJun 182.7 kWh
Solar energy (kWh/m²)Level
Jan7.3Intense
Feb6.5Intense
Mar5.2Bright
Apr3.9Moderate
May3.0Moderate
Jun2.8Moderate
Jul3.1Moderate
Aug4.1Bright
Sep5.2Bright
Oct6.1Intense
Nov7.2Intense
Dec7.6Intense

Where is San Luis?

San Luis sits at 33.3°S, 66.3°W, 729 m above sea level, in Argentina. The nearest listed city is Villa Mercedes, 91 km away.

Rodeo del MedioGeneral Alvear

Topography around San Luis

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

Within 3 km, the terrain around San Luis has only modest variations in elevation — a maximum elevation change of 121 m around an average of 743 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,416 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,820 m.

The land around San Luis is covered by artificial surfaces (72%) within 3 km, shrubs (50%) and grassland (24%) within 16 km, and shrubs (59%) and grassland (22%) within 80 km.

3 km
121 m
16 km
1,416 m
80 km
1,820 m
treesshrubsgrasslandcroplandartificial surfacesbare terrain
Nearby: Villa Mercedes 91 km · Villa Dolores 184 km · Río Cuarto 184 km · Rivadavia 199 km · San Martín 201 km · Embalse 217 km · Rodeo del Medio 222 km · General Alvear 226 km

Argentina travel facts

Travel advisory
Level 1
Exercise Normal Precautions
Power plugs
Type C / I
220 V · 50 Hz
Prices
≈ 46% of US
price level, 2025
GDP per capita
$14,898
2025
Happiness
6.4 / 10
World Happiness, 2025
Homicide rate
4.5
per 100k, 2023
Road deaths
14.1
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
High
EF EPI 575
Religion
Roman Catholic 63%none 19%Evangelical 15%Jehovah's Witness and Church of Jesus Christ 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 (-33.2914°, -66.3247°, elevation 729 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).