May is the turn. The rains arrive, usually in the first half of the month, and within a fortnight the brown valley goes green. It is still hot – about 32°C in the city – and it is still low season on price, which makes it one of the most underrated months to be in Oaxaca.
The numbers
How the rainy season actually works here
This is the single most useful thing to understand about Oaxaca between May and October, and it is nothing like a monsoon.
- Mornings are clear. Almost every day starts sunny. Cloud builds through the afternoon.
- Rain falls late in the day – typically a heavy thunderstorm between about 4pm and 9pm, lasting one to three hours.
- It rarely rains all day. A whole-day washout is unusual outside a tropical system.
- Plan outdoor things for the morning and you will lose almost nothing to the weather.
- Dirt roads get harder – the Hierve el Agua road and some palenque tracks can be rough after heavy rain.
The valley turns green
The transformation is genuinely dramatic. The hills around Monte Alban go from dust to green within about two weeks of the first real storms, the Sierra fills with cloud, and the light softens. If your image of Oaxaca is the brown one from the guidebooks, the rainy season is the version most people never see.
The coast in May: surf, heat and the season boundary
- The Pacific hurricane season officially opens on 15 May and runs to 30 November. Early-season systems are uncommon and usually weak, but the season is real and worth tracking if you are on the coast.
- The big swells start. Zicatela at Puerto Escondido builds through May towards the summer season, and it is a serious wave – not a beginner break.
- It is hot and humid, in the low thirties with high humidity, which feels very different from the dry valley.
- Prices are low and the beaches are empty until the Mexican summer holidays start in mid-July.
What May is good for
- Low prices and no crowds – along with April and September, the cheapest stretch of the year.
- Green landscapes without the heavy rain of July to September.
- Monte Alban and Mitla in the morning, with better air than the hazy late dry season.
- The Sierra Norte, cool and cloud-forested, just as the rains bring it to life.
- Mothers’ Day, 10 May, which in Mexico is a fixed date and a big family occasion – restaurants are full and mariachis do the rounds.
Where to go in May
- Oaxaca City and the central valleys, green and quiet.
- The Sierra Norte – Cuajimoloyas and the Pueblos Mancomunados, at their best as the cloud forest wakes up.
- Puerto Escondido for surf and empty beaches, with an eye on the forecast.
- Teotitlan del Valle and the craft villages, uncrowded now.
- Mercado 20 de Noviembre and the valley markets, which never stop.
Prices and crowds
Low season, and among the best value of the year. The 1 May and 10 May dates fill restaurants but not hotels. Rates stay low until the Mexican summer holidays begin in mid-July. See what a trip to Mexico costs.
What to pack
Light clothes plus a genuinely waterproof layer and quick-drying shoes – afternoon storms are heavy. A light jacket for evenings at about 15°C. Strong sunscreen for the clear mornings. Insect repellent, which matters from May onwards as the rains begin. A dry bag or case for a phone if you are out in the late afternoon.
The May 2027 calendar
- Saturday 1 May – Labour Day, a federal public holiday across Mexico.
- Monday 10 May – Mothers’ Day, a fixed date in Mexico and a major family occasion. Not a public holiday, but book a restaurant table.
- Saturday 15 May – the official start of the Pacific hurricane season, which runs to 30 November.
- Through May – the first sustained rains, about 68 mm, arriving as late-afternoon thunderstorms.
- Mid to late May – the valley turns green, usually within a fortnight of the first storms.
- Through May – the Zicatela swell builds at Puerto Escondido.
Read alongside
- Oaxaca in April – the hottest, driest month.
- Oaxaca in June – deep green and no crowds.
- Oaxaca in July – Guelaguetza.
- Best time to visit Oaxaca – all twelve months compared.
- Oaxaca travel guide – the city, the valley and the coast.
- Oaxaca itinerary – how to put a trip together.
- Things to do in Oaxaca – the year-round list.
- Oaxaca food guide – moles, tlayudas and the markets.
Frequently asked
When does the rainy season start in Oaxaca?
Usually in May, sometimes in late April. It builds through June and peaks in June and September.
Does it rain all day in Oaxaca in the wet season?
No. Mornings are almost always clear and storms come in the late afternoon and evening, typically lasting one to three hours. Plan outdoor activities before lunch.
Is May a good time to visit Oaxaca?
Yes, and it is underrated. The valley turns green, prices are at low-season levels, the crowds have gone, and the rain is easy to work around.
When does hurricane season start on the Oaxaca coast?
The Pacific season officially runs from 15 May to 30 November, with the most active period in late summer and early autumn. Early-season systems are uncommon.
How hot is Oaxaca in May?
About 32°C by day in the city, with nights near 15°C. The coast is similar in temperature but much more humid.
Is May good for surfing at Puerto Escondido?
The swell builds through May towards the summer season. Zicatela is a heavy, hollow wave and is not a beginner break at any time of year.
When is Mothers’ Day in Mexico?
10 May, on a fixed date rather than a Sunday. It is a major family occasion, so restaurants book out even though it is not a public holiday.
Do I need insect repellent in Oaxaca?
From May onwards, yes, especially on the coast and in the valleys after the rains start.
Oaxaca month by month
- January – dry, bright days and genuinely cold nights.
- February – carnival, Candelaria and perfect dry-season weather.
- March – Semana Santa, jacarandas and the heat building.
- April – the hottest and driest month, just before the rains.
- May – the rains arrive and the valley turns green (this page).
- June – clear mornings, afternoon storms, and no crowds.
- July – Guelaguetza, the biggest festival of the year.
- August – deep green season and the quietest city of the year.
- September – Independence, the wettest month and the hurricane peak.
- October – Dia de Muertos and the end of the rains.
- November – dry, clear and arguably the best month of all.
- December – Noche de Rabanos, posadas and the Christmas peak.
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Written by
John Morrison is the founder and lead travel writer at Packzup. Over the past decade he has explored destinations across Africa, the Americas, Asia, Europe, the Middle East, and Oceania — always self-funded, never on a press trip.
