What to Wear in Mexico City in January

Pack for breakfast and lunch separately. SMN's 1991–2020 normals for its Tacubaya observatory give January 22.2°C by day and 8.3°C at dawn, the lowest normal minimum of the year, with 12mm of rain over about 3 days, and the station's January record is 1.0°C. Conagua notes that El Niño, established this year, "suele favorecer temperaturas por debajo del promedio en gran parte del centro y norte del país" in winter, and SMN forecasts eight cold fronts for January. Then the sun. SEDEMA says the city's altitude exposes it to about 20% more ultraviolet than sea level, with the riskiest hours from 11am to 4pm, and that winter is the season of suspended particles, when an inversion leaves "nulo movimiento del aire" and pollutants build up for hours. A packable down jacket for 8am, a shirt and a hat for noon, a scarf for your face in between.

The capsule

1. 
   01

   Cream packable down jacket, stand collar

   Tacubaya's normal January low is 8.3°C, the coldest of the year, and the city's tourism office warns that winter early mornings "will sometimes drop close to freezing". A light down jacket takes the chill off an 8am walk and squashes into a tote by noon, when it is 22°C. Cream keeps it from looking like ski gear in a Roma café.

2. 
   02

   Black chunky ribbed roll-neck

   Mexico's civil protection agency tells people to dress in layers in a cold snap, "cubriendo rostro, cabeza, manos y oídos". A roll-neck covers your neck at dawn without a separate scarf, ribbed wool holds warmth under the down, and black sits with the faded jeans and the boots.

3. 
   03

   Pale blue oversized cotton shirt

   Noon is 22.2°C, and SEDEMA puts the riskiest UV hours at 11am to 4pm. An oversized cotton shirt with long sleeves covers your arms once the down and the roll-neck come off, and pale blue stays cool in direct sun at 2,240 metres.

4. 
   04

   Faded black straight jeans

   One pair from a cold breakfast to a dinner in Condesa. Faded black denim takes both the chunky knit and the blue shirt, sits straight over the Chelsea boots, and covers your ankles when the temperature drops after sunset at about 6:20pm.

5. 
   05

   Black leather Chelsea boots, lug sole

   Stone streets hold the night's cold at 8am and are dry by noon in a month with about three wet days. A Chelsea boot pulls on over wool socks and walks all day on a lug sole.

6. 
   06

   Straw hat, wide brim, chocolate ribbon

   Mexico City's tourism office says "a hat and sunscreen will make many travelers much more comfortable" at almost any time of year, and SEDEMA's extra 20% of UV is why. A straw brim shades your face and neck from 11am to 4pm. Take it off at the Casa Azul, which asks visitors to enter without hats or caps; on the Zócalo, Sombreros Tardan sells a UV-protection line if you arrive without one.

7. 
   07

   Ivory pashmina, pale blue border

   Civil protection also advises covering your nose and mouth when you leave a warm room for the cold outside, which a thin pashmina does at dawn. At dinner it goes over your shoulders instead of a second jacket, and ivory lifts the black knit.

8. 
   08

   Oxblood leather camera crossbody

   Worn in front on a crowded Metro or at the Monumento a la Revolución around Día de Reyes on 6 January, when the city's tourism office says children bring their letters to the Three Kings. Oxblood is the one warm colour in a capsule of black, cream and blue.

A suggested look — cream down puffer jacket, black chunky roll-neck sweater, faded black straight jeans, black chelsea boots, ivory and pale blue scarf.

What to avoid

• A hat or sunglasses inside the Casa Azul — enter without them
• The Frida Kahlo museum on 1 January — closed
• A light jacket as the only warm layer — the January record is 1.0°C
• A hard run on a still, hazy morning — inversions trap pollutants
• Trusting cloud to block the sun — it does not block the UV