San Miguel de Allende weather, month by month

What is the weather in San Miguel de Allende like through the year?

It is a year in two halves: a dry, sunny season from November to April and a rainy season from June to September, with May and October as the hinges. In the town's normal, June to September brings 469.5 of the 631.8 mm of rain a year, or 74%, while November to April together bring 79.1 mm, about 12.5%.

The weather in San Miguel de Allende is also mild in both directions: the warmest month is May, with a normal high of 30.8 °C, and the coldest is January, with a normal low of 4.6 °C. The table sets out San Miguel de Allende weather by month as the station records it, without rounding.

The station has between 25 and 28 years of data in each column. It describes the climate of the town as a whole, not of a particular street or hillside.

Which months are coldest, and how cold do the nights get?

December, January and February are the coldest months, with normal lows of 5.1, 4.6 and 6.3 °C, and on the coldest nights of the record the temperature has gone below zero. The lowest reading at the town's station is −8 °C, in February 2006, followed by −6 °C in November 2006.

San Miguel de Allende weather in January is the clearest example of the gap between day and night: a normal high of 22.4 °C and a normal low of 4.6 °C, with 2.2 days of rain.

San Miguel de Allende weather in December is almost as cold, at 23.0 °C by day and 5.1 °C by night, and it is also the driest month of the year, with 5.5 mm of rain. For a house, these are the months of water heaters, gas connections and rooms that never get the sun.

When does the rain come to San Miguel de Allende?

It comes in June and leaves in October: June brings 114.7 mm, July is the wettest month with 146.8 mm on 13 days, and by October the total is down to 43.2 mm. Before June, May is the month of the first storms, with 40.0 mm.

A single day can bring a large share of a month. The wettest day on the station's record brought 110.3 mm, on 16 August 2002, more than a normal August, and July 1991 brought 334.6 mm in a single month.

San Miguel de Allende weather in October is the tail of the season: 43.2 mm on 4.6 days, a normal high of 25.3 °C and a low of 10.3 °C. San Miguel de Allende weather in November is already the dry season, with 19.3 mm on 2.5 days and nights at 7.7 °C, and it is the month when the damage of the summer, if there was any, becomes visible on the walls.

What does a dry highland climate at 1,900 metres do to a stone house?

It hides the water rather than showing it: the air dries the surface of a wall long before the water that came through the roof has left it. At La Begoña, another official station in the same municipality, the normal records 1,894.8 mm of evaporation against 612 mm of rain a year, and even in July evaporation is greater than rainfall.

So the damage enters through the roof in the rainy season and shows itself months later on the inside. The guidance of Mexico's national institute of anthropology and history on preventive conservation asks owners of historic buildings to keep roofs clear, para evitar la obstrucción de gárgolas y bajadas de agua, and warns that a blocked downpipe can cause un gran problema de humedad en el interior.

The same guidance says where a flat roof opens first: it is important to detectar grietas y fisuras en la superficie de las cubiertas en las uniones con los pretiles, the low walls around the roof. What cantera stone and a house in the historic centre ask for beyond the weather is covered in the guide to living in San Miguel de Allende.

Which months is the house most likely to be in use?

That depends on its owner, but the town's busiest stretch is known: the municipality describes September and October as una de las temporadas de mayor actividad, with the patriotic and patron-saint festivities running from early September to 11 October in 2026. Outside those weeks, the dry and mild months from November to April are the kindest of the year to be in the house.

The overlap matters. A house that is opened for the festivities in September is opened during the last of the rains, when a leak from July may still be drying inside a wall, and a house that is opened in December is opened in the coldest weeks of the year. Either way, the house should have been checked before anyone arrives, not on the day.

What should be checked in each season?

Before June, everything that takes water off the house; after the rains, everything the water could have reached. A third, smaller visit in December covers what the cold asks for.

In April or May: roofs swept, spouts and downpipes cleared and tested, the joints between roof and parapet checked for cracks, and any waterproofing decided in the dry months, not in July. In October or November: walls, ceilings and the frames of doors and windows inspected for stains, and the humidity of closed rooms measured. In December: water heaters, gas connections and the rooms that never get sun. It is the ordinary work of preventive maintenance, and the dates belong in an annual plan agreed before the season starts.

Each visit is worth something only if the owner can see it from far away, with photographs and dates, which is what owner reporting is for. How the coast compares, month by month, is in the guide to the weather in Acapulco.