Climate in Southwest Mexico

Average daytime and nighttime temperatures

All climatic diagrams on this site result from the collected data from 25 measuring weather stations in Southwest Mexico.
Weather stations at an altitude above 1920m have not been included.
All data correspond to the average monthly values of the last 20 years.

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The climate is very warm with an annual average of 30 degrees, but has few truly tropical and sultry months. It is warm to hot all year round and invites to bathe at average water temperatures of 27 degrees. Dued to the lesser rain the best time for traveling is from November to April. Most precipitation decrease from June to October.
Overview: Climate in Mexico
Daylengths and sun positions in Mexico
Compare climate with other regions or countries
Hours of sunshine per daySunshine hours per day in Southwest Mexico
The number of hours of sunshine refers to the time when the sun is actually visible. That is, without any obstruction of visibility by clouds, fog or mountains. With 9 hours per day, April is the sunniest month in the region of Southwest Mexico. In September the sun shines the shortest.
Rainy days per monthRainy days per month in Southwest Mexico
A rainy day is a day on which at least an amount of 0.1 mm precipitation (=0.1 liter) per square meter falls. This can be rain, snow, hail or even dew. So it does not have to rain the whole day. With 16 rainy days, September offers the most number of rainy days, and in February the least.
Precipitation in mm/dayPrecipitation in Southwest Mexico
The amount of precipitation is measured in millimeters per square meter. Thus, at two mm/day, two liters of water fall on one square meter within 24 hours. With only 0.7 mm, the least rain falls in March. September, on the other hand, has the most rain.
Water temperatureWater temperatures in Southwest Mexico
Water temperature depends not only on solar radiation within the same region, but also on ocean currents. For example, depending on the season, cold or warm water masses are moved from other areas. The warmest temperatures in Southwest Mexico are in August, when the water is 29 °C.
Relative humidity in %Relative humidity in Southwest Mexico
Warm air can absorb more moisture than cold air. The relative humidity indicates how much moisture of the physically possible is actually contained in the air. At high humidity, the person feels uncomfortable and perceives this as oppressive. In general, a relative humidity of 40-60% gives as pleasant. With humidity averaging 81%, September is the most uncomfortable. In February, on the other hand, it is easier to endure.
Absolute humidity in g/m³Absolute humidity in Southwest Mexico
In warm months, there is also a higher absolute humidity almost everywhere. At a temperature of 25°C, air can absorb up to 23 grams of water per cubic meter. At 20°C, it is only 17.3 grams. A relative humidity of 40% at 25°C thus corresponds to an absolute humidity of 9.2 grams of water. From a proportion of approx. 13.5 grams, humans perceive the air as muggy. This limit is exceeded throughout the year in Southwest Mexico.
Humidex in °CHumidex in Southwest Mexico
The "Humidex" (humidity index) is an index of well-being in warmer areas, calculated from the air temperature, relative humidity and dew point. The index corresponds approximately to the temperature felt. At high temperatures, the body transports heat away by sweating. At high humidity the ambient air can only absorb a small amount of sweat and thus one feels uncomfortable. An index of 20-29 is considered comfortable. Up to 39, people perceive the air as slightly uncomfortable, and above 40, as very uncomfortable. Values above 45 are dangerous in the long run and often lead to heat stroke.
Map of Southwest Mexico

Most important cities in the region »Southwest Mexico«

Alone 2 major cities with over 500,000 inhabitants are located here. The region has a west-east extension of about 1160 km and over 750 km from north to south.

It consists of the three federal states Chiapas, Guerrero and Oaxaca.

CityPopulationGeo position
Acapulco de Juárez673,47916° 51' 48"N99° 53' 24"W
Tuxtla Gutiérrez537,10216° 45' 35"N93° 6' 47"W
Oaxaca de Juárez255,02917° 3' 56"N96° 43' 25"W
Tapachula197,96114° 54' 25"N92° 15' 43"W
San Cristóbal de las Casas185,91716° 43' 54"N92° 38' 29"W
Chilpancingo de los Bravos165,25017° 33' 2"N99° 30' 21"W
Iguala de la Independencia112,10618° 20' 57"N99° 32' 22"W
Las Margaritas103,40316° 18' 46"N91° 58' 52"W
Tuxtepec92,12118° 5' 18"N96° 7' 31"W
Comitán79,94416° 14' 41"N92° 8' 3"W
Salina Cruz73,64816° 11' 3"N95° 12' 5"W
Juchitán de Zaragoza67,63716° 26' 10"N95° 1' 11"W
Santa Cruz Xoxocotlán61,84617° 1' 46"N96° 44' 7"W
Ixtapa-Zihuatanejo61,30817° 38' 36"N101° 33' 8"W
Taxco de Alarcón53,21718° 33' 23"N99° 36' 18"W
Ciudad de Huajuapan de León47,84417° 48' 28"N97° 46' 46"W
San Luis de la Paz47,32121° 17' 52"N100° 31' 0"W
Santo Domingo Tehuantepec37,38916° 19' 29"N95° 14' 28"W
Tlapa de Comonfort36,87317° 32' 26"N98° 34' 46"W
Palenque36,66917° 30' 34"N91° 58' 57"W
Cintalapa de Figueroa33,46416° 41' 2"N93° 43' 5"W
Tonalá32,85516° 5' 19"N93° 45' 21"W
Chiapa de Corzo32,18216° 42' 28"N93° 0' 43"W
Ocozocoautla de Espinosa31,59616° 45' 44"N93° 22' 29"W
Huixtla29,25715° 8' 25"N92° 27' 57"W
Ocosingo28,72116° 54' 23"N92° 5' 37"W
Malinaltepec26,61317° 14' 42"N98° 40' 15"W
Santiago Pinotepa Nacional25,66916° 20' 18"N98° 3' 19"W
Ciudad Altamirano24,53318° 21' 30"N100° 40' 11"W
Chilapa de Alvarez23,66517° 35' 41"N99° 10' 35"W

Data basis: German Weather Service, individual values averaged and supplemented by own elements. Data on cities and inhabitants:, United Nations Statistics Division and own research.
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