MEXICO · DECEMBER · SONORA
December turns Puerto Penasco from a swimming trip into a beach-walking, sun-on-the-sand trip. Afternoons average 67.4°F, nights fall to 52.7°F, and rain barely registers. The Sea of Cortez is still right there, but at 65.4°F it is no longer the main event for most visitors.
The real choice is between December and the weeks on either side of it. November afternoons average 8.4 degrees warmer, while January afternoons sit 0.2 degrees below December’s.
DECEMBER AT A GLANCE · PUERTO PENASCO
December in Puerto Penasco is a mild, dry month for walking the beach, with 67.4°F afternoons, 52.7°F nights and a 65.4°F sea that suits a quick dip more than a swim.
MILD DAYS · COOL NIGHTS · 65.4°F SEA · 1.3 RAIN DAYS
Go for: dry, mild beach days, almost no rain, and a sea that still allows a brisk dip at Sandy Beach or Cholla Bay.
Think twice if: a long, warm swim is the plan. November’s sea runs 72.1°F, December’s 65.4°F.
Air: ERA5 via Open-Meteo · Sea: Open-Meteo Marine API · Daylight: sunrise-sunset.org · full sources below
On this page
- Puerto Penasco weather in December67.4°F highs, 52.7°F lows, 1.3 rain days, 10 h 10 min of daylight
- Can you swim in Puerto Penasco in December?Sea at 65.4°F, and why that is a mean of daily maxima
- Puerto Penasco hotel prices and crowds in DecemberWhat we could not verify on rates, plus Sonora’s 3% lodging tax
- Things to do in Puerto Penasco in DecemberSandy Beach, Cholla Bay and the Alto Golfo biosphere reserve
- Puerto Penasco itinerary for DecemberTwo days built around a 7:24 a.m. sunrise and a 5:34 p.m. sunset
- Puerto Penasco in December vs November and JanuaryHighs, lows, rain and sea temperature for all three months
- Is December a good time to visit Puerto Penasco?Who it suits, when to go instead, and the State Department’s Level 3 advisory
Most U.S. visitors still arrive by car through the Lukeville-Sonoyta border crossing. Short December days argue for crossing with daylight to spare.
Puerto Penasco weather in December
| Puerto Penasco, December | Average |
|---|---|
| Average high | 67.4°F |
| Average low | 52.7°F |
| Precipitation | 0.58 inches |
| Days with 0.10 inch or more | 1.3 |
| Days with 1 inch or more | 0.0 |
| Daylight on December 15 | About 10 h 10 min |
The air figures here are 1991-2020 normals from the ECMWF ERA5 reanalysis, served by Open-Meteo. That makes them a model, not a thermometer. They are computed for a grid cell over Puerto Penasco, and none of the town’s three CONAGUA stations publishes a normals product. A grid cell on this stretch of the Sea of Cortez may soften the desert coast’s sharp day-night swing, so real nights can feel sharper than the model’s 52.7°F average low.
An average December brings 0.58 inches of precipitation, spread over 1.3 days that reach 0.10 inch or more. No December day in the record averages a full inch. In a real trip that is a single damp day in the whole month, and a light shell jacket covers it.
Afternoons peak at 67.4°F and nights bottom out at 52.7°F, a swing of 14.7 degrees. T-shirt weather in direct sun turns into sweater weather by dinner. Pack layers: a fleece or sweater for evenings, a windbreaker, and long pants alongside the shorts.
On December 15 the sun rises at 7:24 a.m. and sets at 5:34 p.m. in Sonora (Hermosillo) time, about 10 hours 10 minutes of daylight. Beach time ends in late afternoon, and dinner happens after dark.
Can you swim in Puerto Penasco in December? Sea temperature
The Sea of Cortez off Puerto Penasco averages 65.4°F in December, from the Open-Meteo Marine API over 2015-2024. That number is a mean of daily maxima, so it runs a shade warmer than a 24-hour average would. Other sea tables built on 24-hour means will read lower.
For anyone stepping in, 65.4°F is a brisk plunge, not a warm soak. A short dip at Sandy Beach (Playa Mirador) or Cholla Bay, both swimming beaches on the Sea of Cortez, suits the cold-water crowd. Leave a towel and a dry layer waiting on the sand.
We found no December wind or swell data for the Puerto Penasco coast, so we give none. Check a marine forecast on the morning you plan to get in.
How busy is Puerto Penasco in December? Crowds and prices
We found no occupancy series, no visitor counts and no monthly room-rate series for Puerto Penasco. So we place December nowhere on the year’s price curve and crown no month cheap or expensive. Christmas and New Year’s both fall inside the month, so the last two weeks are the dates to ask about first.
Without booking-window data, we give no number of weeks to reserve ahead. Ask each property about minimum stays and deposit terms for holiday dates, and get the cancellation rules in writing before you pay.
Sonora’s lodging tax is 3% of revenue under Article 122 of the state’s Ley de Hacienda (text published December 26, 2025). We could not verify how an individual property shows it on the bill, so ask whether a quoted rate already includes it.
With the sea at 65.4°F, one extra worth asking about is a heated pool. We could not verify which properties heat theirs in winter, so it is a question for the front desk before you book.
Things to do in Puerto Penasco in December
December suits days on foot. Afternoons average 67.4°F, rain shows up on 1.3 days, and the light is soft enough for long beach walks, slow lunches outdoors and sunset watching from the sand.
Two beaches anchor the swimming options: Sandy Beach (Playa Mirador) and Cholla Bay, both on the Sea of Cortez. We could not verify entry fees, parking charges or hours for either, so none appear here. Call ahead or ask your hotel.
The water at both beaches drops from 72.1°F in November to 65.4°F in December. The air falls 8.4 degrees at the same time. That is why a beach day in December is a walk, a picnic and a quick dip rather than an afternoon in the surf.
Puerto Penasco sits at the edge of the Alto Golfo de California y Delta del Rio Colorado Biosphere Reserve, decreed a federal protected area on June 10, 1993. It is the critical refuge of the vaquita marina, the world’s most endangered marine mammal, and of the totoaba fish. We found no verified list of free activities or boat-tour tariffs, so we quote none.
Puerto Penasco itinerary for December
First day: sunrise is at 7:24 a.m., and nights bottom out near 52.7°F, so start with a layer and a slow breakfast. Head to Sandy Beach (Playa Mirador) in mid-morning as the air warms, walk the shoreline, and take the dip in early afternoon when highs approach 67.4°F. Be off the sand before the 5:34 p.m. sunset, then have dinner in town.
Second day: spend the warm middle of the day at Cholla Bay, then use the last daylight for a shoreline walk. Rain is rare, with 1.3 days at 0.10 inch or more in an average month. If a damp day lands here, keep the beach for the afternoon after it clears and take the morning slowly.
Puerto Penasco in December vs November and January
| Measure | November | December | January |
|---|---|---|---|
| Average high | 75.8°F | 67.4°F | 67.2°F |
| Average low | 60.6°F | 52.7°F | 51.9°F |
| Precipitation | 0.29 inches | 0.58 inches | 0.36 inches |
| Days with 0.10 inch or more | 0.6 | 1.3 | 1.1 |
| Sea surface (Marine API) | 72.1°F | 65.4°F | 62.3°F |
Air normals for all three months share the same ERA5 grid cell and the same 1991-2020 period. From November to December, afternoons drop 8.4 degrees and nights drop 7.9 degrees. From December to January the air barely moves, down 0.2 degrees by day and 0.8 degrees by night. The sea, from the Marine API, falls 6.7 degrees into December and another 3.1 degrees into January. December is the wettest of the three at 0.58 inches, against 0.29 in November and 0.36 in January.
Shifting four weeks earlier to November gains 8.4 degrees in the afternoon and 6.7 degrees in the sea, and it is drier. Shifting four weeks later to January costs 3.1 degrees of sea warmth and gains 0.22 inches less rain. We found no price or crowd series to compare, so cost stays an open question. For other destinations by month, browse where to go month by month.
Is December a good time to visit Puerto Penasco?
Yes for walkers, sun-on-the-sand people and anyone who wants dry days: 67.4°F afternoons, 1.3 rain days and about 10 hours of daylight. No for anyone whose plan is long swims. Also check the State Department’s Mexico advisory, reissued May 29, 2026, which lists the State of Sonora at Level 3, “Reconsider travel, due to terrorism and crime.” We read it on September 29, 2026. Read the Sonora entry before you book and again before you drive.
If the water is the point, aim for November: a 72.1°F sea and 75.8°F afternoons. Skip January in that case, since its sea is the coolest of the three at 62.3°F. If beaches are not the point, browse other destinations.
December keeps January’s air at 67.4°F while holding the sea 3.1 degrees warmer, at 65.4°F against 62.3°F.
The last word
December in Puerto Penasco is a fleece-and-sunglasses month: 67.4°F afternoons, 52.7°F nights and a sea that asks for a quick dip. If you would rather skip the border drive, Mar de Cortes International Airport went more than five years without scheduled commercial flights, and a new scheduled route resumed in mid-2026. Confirm current flights before you book, and browse our Travel 101 guides for planning basics.
Sources & data for this guide
- Air normals 1991-2020 · Open-Meteo / ECMWF ERA5 reanalysis for the grid cell over Puerto Penasco (a model, not a station reading; none of the town’s three CONAGUA stations publishes normals) · checked Sep 30, 2026
- Sea surface, mean of daily maxima 2015-2024 · Open-Meteo Marine API · checked Sep 30, 2026
- Sunrise, sunset and daylight on December 15 · sunrise-sunset.org, converted to Hermosillo time · checked Sep 30, 2026
- Biosphere reserve decree of June 10, 1993 · CONANP · checked Sep 30, 2026
- Airport service · local press (Codigo Rojo Cajeme, Ahora Noticias Penasco) · checked Sep 30, 2026
- Lodging tax, Article 122 · Congreso del Estado de Sonora, Ley 9, De Hacienda del Estado de Sonora · checked Sep 30, 2026
- Travel advisory, Sonora · U.S. Department of State, Mexico Travel Advisory (reissued May 29, 2026) · checked Sep 30, 2026
- We found no occupancy, room-rate, hours or admission data for Puerto Penasco, so none appears. Beach descriptions are common knowledge · check operators when you book.