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San Luis weather by month: averages, rainfall & climate trends

San Luis has well-marked seasons, with 14.0°C between its warmest and coolest monthly means. Rainfall leans toward the stretch from October to March. San Luis weather by month: average temperatures, rainfall, records and how the climate has changed since 1940.

Today vs average

−5.1°Chigh well below average

19° / 8°Today
24° / 13°Average
see today in detail →

How it's changed

+1.8°Caverage temperature, 2016–2025 vs 1940–1949average temperature vs 1940–495frost days a year now (2016–2025) · 4 in the 1940sfrost days a year · 4 in the 1940s90days above 30°C a year now (2016–2025) · 22 in the 1940sdays above 30°C · 22 in the 1940s+1.8°C vs the 1940s · see how it's changed →
Weather by montha typical year, averaged over the full recordJanuary, rain 116 mmhigh 30°low 19°February, rain 95 mmhigh 29°low 18°March, rain 88 mmhigh 26°low 16°April, rain 49 mmhigh 23°low 12°May, rain 28 mmhigh 19°low 9°June, rain 13 mmhigh 17°low 6°July, rain 16 mmhigh 16°low 5°August, rain 17 mmhigh 19°low 7°September, rain 41 mmhigh 21°low 9°October, rain 76 mmhigh 24°low 12°November, rain 97 mmhigh 27°low 15°December, rain 108 mmhigh 29°low 18°wettest month January, 116 mm · 744 mm a yearsee month by month →

Right now

What it's doing today vs the historical average for this date.
Mostly clear

Right now

15.1°

12°feels like
59%humidity
7°dew point
18 km/hfrom SE
UV index0.1
sunrise06:44sunset19:38day length12h 54m
TodayPartly cloudy19°8°
FriOvercast18°8°
SatOvercast20°9°
SunOvercast21°10°
MonOvercast16°13°
TueMostly clear21°11°
WedShowers20°14°

On this date: October 15

Today (forecast)
19° / 8°
Average for October 15
24° / 13°

High well below average · −5.1°C

  • Record high: 35.6° · 2003
  • Record low: 3.4° · 1959
  • One year ago: 33° / 19°

Every October 15 in history, coldest to hottest

▲ Daily highs▼ Daily lows

Dots show daily highs (top) and lows (bottom) for each October 15 on record (n = 87). Outlined dots are today's forecast.

Area we sample

Each city's history comes from one ERA5 grid cell, about 28 km across, shown by the dashed box. Near mountains or coasts, conditions can vary across the cell.

Location & data

Historical weather for San Luis is sampled from the ECMWF ERA5 reanalysis at 33.29°S, 66.32°W, with daily records since 1940.

Coordinates
33.29°S, 66.32°W
Time zone
America/Argentina/San Luis
Period
1940–2026
Data source
ERA5 (ECMWF)

Last 30 days

17 of the last 31 days were warmer than the historical average for that date. Average difference: +0.6°C.

Each bar is one day, from morning low to afternoon high. Warm-colored bars are days whose mean ran above average; cool bars ran below. The dot inside the bar is the daily mean. The shaded band is the typical 10–90% range expected for that date. Average = the day's mean temperature averaged across every year of record (1940–2026) for that calendar date.

This date over the years

One dot per year, showing the mean temperature on this calendar date. Dots are warmer or cooler than the long-term average (dashed line); the shaded band is the typical 10–90% range, and the highlighted dot is today's forecast. Based on ERA5 reanalysis: modelled estimates, not station readings.

Weather by month

Average temperatures and rainfall for each month: a typical year, from the full record.

Climate overview

The year peaks in January, at around 29.8°C by mid-afternoon, with nights around 18.9°C. Around 50 nights a year stay above 20°C. In July, the coolest month, afternoons reach about 16.5°C and nights dip to 5.2°C.

In total, San Luis averages about 744 mm of precipitation a year; January is usually the wettest month (116 mm) and June the driest (13 mm).

The record here starts in 1940, and since then the annual mean in San Luis has climbed 1.8°C from the first ten years to the last ten. Days above 30°C have grown noticeably more frequent, from around 20 a year in the first decade to about 90 in the last.

Climate graph (climograph)

January is the warmest month, July the coolest: a yearly swing of 14°C. Wettest month: January (~116 mm). Whole year averages ~744 mm of rain.

Bars = average monthly rainfall (right axis). Lines = average daily high and low (left axis). Average = each month's value averaged across every year of record (1940–2026).

Rainy days by month

About 80 rainy days a year: most in January (~12), fewest in June (~2).

Bars = average number of days with ≥ 2 mm per month. Hover for the monthly rainfall total.

Monthly wind

Average daily peak wind at 10 m, by month.

Monthly solar energy

Average daily incoming solar energy in megajoules per square metre: the record's own proxy for how sunny the month is.

San Luis month by month: what to expect

Typical conditions for each month, averaged across the full record (since 1940). Daylight is the time from sunrise to sunset. Record high/low are the most extreme values in the ERA5 dataset (modelled since 1940), so they can differ from official weather-station readings.

MonthAvg highAvg lowRainRainy daysDaylightRecord highRecord low
January29.8°18.9°116 mm1214.0 h41.0° (2022)7.8° (2019)
February28.7°18.0°95 mm1013.2 h40.8° (2025)4.5° (2023)
March26.3°16.0°88 mm912.2 h37.0° (2023)3.2° (1977)
April22.6°12.4°49 mm511.2 h34.2° (2002)−0.7° (2016)
May19.4°9.0°28 mm310.3 h32.2° (1997)−6.6° (2008)
June16.6°5.9°13 mm29.8 h29.8° (1977)−7.4° (2025)
July16.5°5.2°16 mm210.0 h32.9° (1997)−8.6° (2000)
August19.0°6.9°17 mm210.8 h35.3° (1997)−6.0° (1999)
September21.4°9.5°41 mm411.8 h37.5° (2013)−4.3° (1981)
October24.0°12.4°76 mm812.8 h39.7° (2009)−0.3° (2022)
November26.8°15.4°97 mm1013.8 h39.7° (1987)1.1° (1992)
December29.2°17.8°108 mm1114.2 h42.5° (2023)4.8° (1971)

How it's changed

Year-by-year signals from 1940 to today.

Climate stripes

Annual mean shifted from 1940–1949 to 2016–2025 by +1.8°C.

Each vertical stripe is one year. Color encodes how much that year's annual mean differed from the long-term average. Average = each year's annual mean compared to the average of all years (1940–2026). cooler ← → warmer

Annual mean temperature

Long-term trend: +0.18°C per decade.

One point per year, showing the temperature averaged across the whole year. The dashed line is the least-squares long-term trend. Based on ERA5 reanalysis: modelled estimates, not station readings.

Seasonal warming

Sep–Nov is warming fastest: +0.32°C per decade.

Each faint line is one three-month period's average per year; the bold dashed line is its long-term trend. Different parts of the year often warm at different rates. Based on ERA5 reanalysis: modelled estimates, not station readings.

Hot days vs frost days

Days ≥ 30°C per year: 22.4 early in the record → 90.1 recently. Frost days: 4 → 5.

Thin lines are raw yearly counts; thick lines are the smoothed trend that removes year-to-year noise. The hot-day threshold is auto-picked per city so the line actually moves. Average = a centered 5-year rolling average to smooth weather noise.

Yearly hot & cold extremes

All-time high in 2023, all-time low in 2000: 42.5°C / −8.6°C.

One point per year: the single hottest and coldest day recorded that year.

Annual rainfall

~744 mm/year on average. Last decade: −28% vs that average. Long-term trend: −39 mm per decade.

One bar per year of total rainfall. Dashed line is the long-term average. Average = the average annual rainfall across every year of record (1940–2026).

Day-by-day grid

Each tiny square is one calendar day across the full record, about 30,000 days per city. Use the mode switch above the chart: Anomaly colors each day by how far it ran from the historical average for that date (red = warmer, blue = cooler), Daily mean temp shows the absolute mean temperature for the day (useful to see seasons and heatwaves), and Precipitation shows daily rainfall (useful to spot wet/dry seasons and droughts). Average = the long-term average for that calendar date (1940–2026).

Frequently asked questions about San Luis

Which is the warmest month in San Luis?
On long-term average, the warmest month in San Luis is January (mean daily temperature of about 24.0°C) and the coolest is July (about 10.0°C).
How does today's temperature in San Luis compare to the historical average?
On October 15, 2026, San Luis is forecast to reach a high of 18.5°C and a low of 8.0°C. The long-term average for this date (the full record since 1940) is a high of 23.6°C and a low of 12.7°C, so today's high is 5.1°C cooler than that average.
How much has San Luis warmed since 1940?
Comparing the first decade of the record (1940–1949) with the most recent (2016–2025), the annual mean temperature in San Luis is about 1.8°C warmer.
How much does it rain in San Luis?
San Luis receives about 744 mm of precipitation per year on long-term average, with January typically the wettest month.
What is the average temperature in San Luis?
Over the full record (since 1940), the annual mean temperature in San Luis is about 17.2°C. The warmest month is January and the coolest is July.
What are the average temperatures in San Luis by month?
Average daily highs and lows for each month in San Luis (°C, full record since 1940): January 30°/19°, February 29°/18°, March 26°/16°, April 23°/12°, May 19°/9°, June 17°/6°, July 16°/5°, August 19°/7°, September 21°/9°, October 24°/12°, November 27°/15°, December 29°/18°.
What is the weather like in San Luis in summer?
December to February is summer in San Luis, and it is wet and warm. Afternoons run 29–30°C and nights 18–19°C; January is the warmest month. Rain is steady at around 106 mm a month, spread over roughly 11 days. It is the wettest season of the year.
What is the weather like in San Luis in winter?
In winter, June through August, San Luis is dry and fairly mild. Expect 16–19°C by day and 5–7°C at night, with July the coldest month. Rain falls on about 2 days a month, adding up to around 15 mm. No season is drier.
What is the weather like in San Luis in spring?
In spring, September through November, San Luis is pleasantly warm. September is still 21°C in the afternoon and 9°C at night, November already 27°C and 15°C. Rain rises from 41 mm on 4 days in September to 97 mm on 10 days in November.
What is the weather like in San Luis in autumn?
March to May is autumn in San Luis, and it is pleasantly warm. March still brings 26°C afternoons and 16°C nights, May only 19°C and 9°C. Rain falls off from 88 mm on 9 days in March to 28 mm on 3 days in May.
How many days a year does it rain in San Luis?
On long-term average, San Luis has about 80 days a year with at least 2 mm of rain or snow. The annual total is roughly 744 mm.

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