You pack for Mexico. You’re thinking shorts, sandals, and maybe a linen shirt for those breezy tropical vibes, right? Wrong. If you land in Mexico City expecting a Caribbean heatwave, you’re going to be sprinting to the nearest Zara for a puffer jacket.
Mexico City—or CDMX as the locals call it—isn't a beach. It’s a high-altitude metropolis perched 7,350 feet above sea level. That’s higher than Denver. Because of this elevation, the weather Mexico City CDMX provides is a weird, fickle beast that locals describe as "four seasons in one day."
I’ve seen tourists shivering in the Zócalo in January because they thought "Mexico equals hot." It’s a classic mistake. Honestly, the climate here is more like "eternal spring," but a spring that has a bit of a temper.
The Two-Season Reality of CDMX
Forget Winter, Spring, Summer, and Fall. In the Valley of Mexico, we basically deal with two primary modes: the Dry Season (November to April) and the Rainy Season (May to October).
During the dry months, the air is crisp. The sky is a deep, impossible blue. It’s beautiful, but it’s a trap for the unprepared. In January, the sun will bake you at midday, pushing temperatures to a comfortable 72°F (22°C). But the second that sun dips behind the skyscrapers? Boom. It drops to 40°F (4°C).
You’ll see locals walking around in heavy wool coats and scarves at 8:00 AM, looking like they're in London. By 2:00 PM, those same people are in T-shirts. By 8:00 PM, the coats are back.
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Why the Rain Isn't a Dealbreaker
Then there's the rainy season. It sounds ominous. People hear "rainy season" and cancel their flights. Don't do that.
The rain in CDMX is remarkably punctual. From June through September, you can almost set your watch by it. The mornings are usually glorious—sunny, warm, and perfect for a walk through Chapultepec Park. Then, around 4:00 PM or 5:00 PM, the clouds roll in over the mountains. The sky turns a bruised purple.
And then it pours.
It’s not a drizzle; it’s a localized apocalypse for about 60 minutes. The streets turn into rivers because the city's ancient drainage system (built on an old lakebed) just can't keep up. But then, as quickly as it started, it stops. The air smells like damp earth and jasmine, the dust is washed away, and the evening is cool and fresh.
The "Hottest" Months Will Surprise You
You might think July is the peak of the heat. Nope. Because of the afternoon rains, July and August are actually quite temperate.
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The real heat hits in April and May. This is the tail end of the dry season. The sun is brutal at this altitude. There’s no rain to cool things down, and the "Urban Heat Island" effect makes the concrete jungle of Polanco and Reforma feel like a furnace. Temperatures can hit the high 80s (30°C+), which feels much hotter when you're 1.5 miles closer to the sun.
Weather Mexico City CDMX: The Altitude Factor
We have to talk about the air. It’s thin. There is about 25% less oxygen here than at sea level. This changes how you experience the weather.
If it’s 75°F in Miami, you’re sweating. If it’s 75°F in CDMX, you feel "just right" because the humidity is so low. But the sun? The UV index here is off the charts. You will get a sunburn in twenty minutes without realizing it because the air feels so cool.
Expert Tip: Always wear SPF 50+, even if it’s cloudy. The high-altitude UV rays pierce through the "smog-and-cloud" layer like a laser.
Air Quality and the Winter "Inversion"
There is a downside to the beautiful, dry winter weather. It’s called a thermal inversion. Cold air gets trapped in the valley, pinning all the city’s smog and pollutants down at street level.
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If you have asthma or sensitive lungs, February and March can be tough. The air gets hazy, and you might feel a scratchy throat. This is why the rainy season is actually a blessing—it’s the only time the air feels truly "clean."
Packing Like a Pro for the CDMX Climate
If you take away one thing from this, let it be the word layers.
- The Base: A breathable cotton T-shirt or light blouse.
- The Mid: A light sweater or a denim jacket.
- The Outer: A packable rain shell (for summer) or a light down vest/jacket (for winter).
- The Feet: Comfortable sneakers with grip. CDMX sidewalks are notoriously uneven, and when they get wet in July, they become skating rinks.
I once spent a week in Roma Norte in October. One day I was wearing a sun hat at a sidewalk cafe, and three hours later I was huddled under a Cantina awning wondering if I should buy a poncho from a street vendor. (Spoiler: I did. It was the best 50 pesos I ever spent.)
Monthly Cheat Sheet for Travelers
- January - February: Bright sun, freezing nights. Best for clear photos of the volcanoes (Popocatépetl and Iztaccíhuatl).
- March - April: Jacaranda season! The city turns purple. It’s getting hot and dusty.
- May: The transition month. Hot, humid, and the first "big" storms start.
- June - September: The wet peak. Lush green parks, cheap hotels, and daily afternoon showers.
- October - November: My personal favorite. The rains stop, the air is clean, and the weather is mild for Day of the Dead.
What to Do When the Weather Turns
If you’re caught in a July downpour, don’t fight it. This is the city’s way of telling you to go inside.
CDMX has more museums than almost any other city in the world. Head into the National Museum of Anthropology or the Palacio de Bellas Artes. Or better yet, duck into a panadería, grab a concha and a hot chocolate, and watch the chaos from behind a window.
The traffic during a rainstorm is legendary. A 10-minute Uber ride will become a 90-minute odyssey. Just walk if you can, or take the Metro, which stays relatively dry (though very crowded).
Actionable Steps for Your Trip
- Check the IMECA index: Download an air quality app to see if it’s a "good air" day before planning a long hike.
- Hydrate twice as much: The altitude and dry air will dehydrate you before you feel thirsty.
- Book rooftop dinners for 2:00 PM, not 7:00 PM: In the summer, you want that view while the sun is out, not while the lightning is hitting the Torre Latinoamericana.
- Respect the sun: Buy a hat. A real one. Your forehead will thank you.
Understanding the weather Mexico City CDMX really comes down to respecting the altitude. It’s a mountain climate disguised as a tropical one. Dress for the shadows, not the sun, and you'll be the only tourist not shivering when the sun goes down over the Paseo de la Reforma.