Mexico is split in two by the Tropic of Cancer, which creates two distinct climatic zones, meaning deciding on the best time to visit Mexico can be tricky. That's where we come in. The north has a temperate climate with colder winters than in the tropical zone in the south, which enjoys generally stable temperatures throughout the year. However, the southern part of Mexico is also very much influenced by variable altitudes. The higher the altitude, the lower the average temperature will be. From an average of 24°C to 28°C on the Yucatan coastline and peninsula (up to 3,280ft altitude), the temperature then drops to less than 20°C between 3,280 and 6,560ft, finally falling to between 8°C and 12°C in the Trans-Mexican Volcanic Belt. When deciding on the best time to visit Mexico, it's important to know that the country has a wet season between June and October throughout much of the country (the rainy season) and that the dry season runs from February to July. Average temperatures are mild in Mexico. With all these factors in mind, most agree that the best time to visit Mexico is between October and April.
Baja California lies between sea and ocean, bordered to the west by the Pacific Ocean and to the east by the Gulf of California. This unique location in north-western Mexico provides a dry, largely sunny and warm climate year-round. The north-west of Baja California is both cool and humid, with a climate similar to that found in the Mediterranean. The wind from the Pacific makes the weather very pleasant. The same can't be said for the Mexicali plain at the north-eastern extremity of the region, which is affected by the desert climate coming from the United States. This means that while it will be warm and sunny for a large period of the year in the north-west of Baja California, in the north-east, summers will be very hot (over 50°C) and the winters cold (below zero). Hence there is a very large range of temperatures, as well as rainfall during the period from December to March, which applies to the whole of the northern part of Baja California.
Southern Baja California has a tropical climate, with a hot, humid period in August and September, during which hurricanes can also occur. The average temperature varies depending on the altitude. In La Paz (12,000ft), the hottest months (but also the most rainy) are July to September (averaging 29°C). The period from March to May is more favourable, with near-zero rainfall and an average temperature of 19-24°C. Conversely, in a city like San Jose del Cabo (which has a very low altitude), average temperatures are pleasant all year round (above 20°C from April to November), although the rain does arrive in September, with just over three inches.
Close to Guatemala, Chiapas has a harsh climate, which isn't all that surprising given this is the southernmost state in Mexico. As elsewhere in Mexico, the weather will vary depending on the altitude: the hot and humid plains with tropical forests are less subject to differences in temperature than the highlands, with a temperate but relatively cool climate. The mountains are generally misty and humid, and you will need to travel to the coasts for 'drier' air. The rainy season in Chiapas runs from May to October, while the dry season runs from November to April.
The Atlantic Coast
Although less developed than the Caribbean coastal area, Mexico's Atlantic coast enjoys pleasant temperatures and strong sunshine. The period running from December to May is hot, and the rainy season only comes afterward (particularly from June to September). There are clear skies on the coasts, thanks to the winds blowing off the Atlantic which chase away the clouds and help keep temperatures feeling pleasant. Night-time temperatures average 22°C, with daytime averages of 29°C in some coastal cities in April and May.
The Yucatan has a tropical climate. As a result, there are two major seasons: the wet season from June to October (with high temperatures), and the dry season from December to March, which is also milder. Visiting the Yucatan in September and October is best avoided, as this is hurricane season. Lastly, be aware that in the Yucatan, the weather will always be warmer and will feel more stifling if you venture inland.
The Sierra Tarahumara
In the Sierra Tarahumara, the climate varies depending on the altitude. On the plateau (from altitudes of 6,230 to 7,200ft) and in the canyons, sometimes peaking at 7,870ft, winters are cold, and summers mild. The area, therefore, has a temperate climate, and the best time of year to visit is from spring to early autumn.
Mexico City has a temperate, high-altitude climate. Although located in an intertropical zone, Mexico City's annual average temperature is largely moderated by its altitude (7,350ft). As in many other places in Mexico, summer is the rainy season, with the average maximum temperature reaching over 23°C from June to September, and rainfall exceeding five inches per month. Winter in Mexico City is dry (humidity is around 60% in December and January) with an average temperature of 14°C. Spring is the hottest season, with average temperatures of 18.7°C in April and 19°C in May, as well as limited rainfall. Spring is, therefore, the best time to visit Mexico City.