When is the best time of year to visit Baja California Sur?
The southern state of the peninsula, Baja California Sur can be divided into three weather regions, the Pacific coastal region, the inland region and the Sea of Cortez region. This is of course a generalization, because like the northern state of Baja California, there are dozens of micro-climates within each region.
For example, the mountainous region in the southern part of the state, including the pueblos of El Triunfo, San Bartolo and Santiago, remain slightly cooler in summer than the rest of the inland region of the peninsula. The higher altitudes can also receive as much as 4 times the amount of rain as the lower plains of the desert in the form of summer thunderstorms.
Baja California Sur looks to the south for the majority of its yearly rainfall. Although a few winter storms make it further south than Guerrero Negro, the state only gets a fraction of its miserly 7.8" of yearly rainfall in the winter. The bulk of the rainfall in the southern portion of the peninsula comes in the summer from tropical rains, and often comes in a matter of hours from a single tropical cyclone. The Baja Sur tropical cyclone season is from mid August through mid October and storms over the past 10 years have proven that pretty much all of the state is at risk during that time. But we'll talk more about hurricanes in their season, further on in this article.
Pacific coastal locations include Guerrero Negro, Magdalena Bay, San Carlos, and Todos Santos. Eastern side locations include Santa Rosalia, Mulege, Loreto, La Paz and East Cape. San Jose del Cabo and Cabo San Lucas reside at the tip of the peninsula and enjoy a little of both the Pacific and Sea of Cortez climates.
In winter our weather patterns across the peninsula come from the north. Pacific storms can bring showers to a full blown downpour to any region of the peninsula, but the chances and the ferocity of the storms diminish as you move south. Although we locals still see winter as winter, it is the favorite time of year for northern folks to come visit to escape the cold. The Sea of Cortez will dip into the low 70's to mid 60's and fishing is more limited. Winds are the strongest on average during the winter months. Temps are usually in the low to mid 70's but a few days could be 10°+/- from that norm. North winds are the significant weather feature in the winter.
Caused by High pressure moving over the 4 Corners Region of the U.S., north winds are the winter bane of much of the southern portion of the peninsula. Because the Sea of Cortez is almost perpetually cooler than the surrounding land mass, a trough, or canyon of air, runs south through the Sea. When a High pressure system moves over the 4 Corners region of the U.S. the clockwise rotation of the system pumps cold air south, down the canyon of air, in an attempt to equalize the barometric pressure. The tropical air is warmer, the molecules further apart, is lighter and begins to rise. Because of the Coriolis Effect, the rising air spins counter-clockwise and a Low pressure system is born. In the winter months the mean air pressure in Baja is about 1012Mb. The cold arctic system over Colorado has dense air, which grows colder in the stratosphere and falls. The falling air spins clockwise and a High pressure system is formed. The strongest High to pass over the 4 Corners region in the winter of 2013 was about 1038Mb.
With the High pumping air into this invisible canyon in the sky, trying to equalize a barometric pressure difference of 25Mb or more strong winds are generated. When this event is about to materialize the barometric pressure along the Sea of Cortez will begin to rise. Winds will begin in the north-northwest and increase until they are coming from the north. As the High pressure moves east from the 4 Corners, the winds will begin to diminish and shift to the north-northeast and finally northeast.
Parades of these cold Highs can stack up from Washington and Oregon and out into the North Pacific. Periods of north winds to 45kts can bring large short period waves as large as three meters. The focal point of the raging winds, their ferocity and duration depend on the strength of the High and the position. A standard norther will blow 25-30kts for 2-4 days, although they can be brief or endure for a week at a time. Norther's begin in late November and can blow strong through mid March. As the northern hemisphere warms the Highs become less intense and move further north and the effect diminishes.
Northers most dramatically effect the Sea of Cortez side of the peninsula, but bring colder temps to most of the state.
Baja Sur sometimes receives winter rains, more prevalent in the north with the odds diminishing as you move south. But a couple times per season La Paz and Los Cabos will get a small Pacific storm that maintains enough strength to reach far south. This past season La Paz received almost 1/4" of rain from a storm moving northeast. This was caused by warmer tropical moisture moving northeast from the Hawaiian Islands running into a dry cold front, moving southeast from California. Many refer to the clouds and moisture that travel northeast as the "Pineapple Express", but that name refers to another specific weather phoneme. This winter flow also brings a majority of the cloudy days to Baja Sur during the winter.
Southwest: Winter is the peak of whale watching season on the Pacific side of Baja California Sur. The Pacific cools off much faster than the Sea of Cortez and winter sets in by late December. Winter storms can work their way this far south in January and will be a persistent possibility through early March. Since the Pacific is the source of this region's cooler climate, it is also damp. Storms have lost a lot of their punch by the time they get this far south, but the Pacific side is more likely to get rain that the Sea side in the winter. The Pacific will provide strong surf and places like Todos Santos attract many surfers in this season. Temperatures begin to warm up by late February and by early March spring and the 70°'s are in the air.
Southeast: Like the northern Sea of Cortez, the north winds bring the most significant weather, blowing cold air from the north down the Sea sometimes to 35kts or more. The most severe north winds blow in January into February and make places like La Ventana popular for wind surfing and kiting. Winter usually begins right after the New Year and there is the occasional Pacific winter storm that will bring a day or two of rain. It is not uncommon for there to be at least one good rain in the winter, of an inch or so accumulation. The Pacific tropical flow brings a bulk of the region's cloudy days during winter and every once and a while a cold front from the north will squeeze a little drizzle from these clouds. Daytime highs are usually in the 70's and over night lows dip to the upper 40's. Things begin to warm up by the end of February.
Cabo San Lucas is the southern most point on the peninsula and straddles the Pacific and Sea of Cortez weather environments. The Pacific winds keep Cabo a little cooler year-round than other places in Baja Sur, but by the time you move just 20 miles to the east in San Jose del Cabo the climate is warmer and drier.
In Winter the weather comes from the north in Baja, in summer, from the south. Spring and fall represent periods when our weather doesn't come from anywhere at all, a never-never land between northern and southern influences.
Spring brings Carnaval to La Paz. The holiday floats with the Easter calendar and can fall as early as the 4th of February. Where the event falls can have a dramatic affect what you should wear to the parades. Early Carnavals, like 2013, provided a few very pleasant 'shirt-sleeves' evenings and a few cold ones as well. Late season Carnavals in lat February or March mean you can probably even leave the sweater at home for the evening.
Southwest: Like the other Pacific coastal areas, this region of Baja Sur warms up more slowly and spring begins in early March. By late month this region has some of the lowest temperature variation of anyplace on the peninsula with temps in the low 80's in the day and low 70's at night. This cooler climate is a benefit to the region well into summer, when inland areas begin to sizzle.
Southeast: Spring is perhaps the most popular tourist season along the Sea of Cortez from Santa Rosalia to East Cape. Once the north winds quit, things warm up beginning in late February. By mid March daytime highs in the 80's make it wonderful for almost all outdoor activities. An occasional north wind will blow through mid March, but they are less ferocious than their mid-winter cousins and less enduring. Clouds may still persist for a couple of days at a time, as that Pacific moisture moves northeast across the peninsula, but sunny skies and shirt sleeves are the norm from late February through April. Daytime highs in La Paz climb from the upper 70's in early March to the upper 80's and low 90's by the end of the month.
It is important to remember the sunscreen from late March onward. The Tropic of Cancer passes through lower Baja Sur and the sun climbs higher in the sky by early April than it ever reaches in Southern California in late June. UV indexes, with our direct angle and low humidity reach maximum in late March and continue dangerous to your skin and eyes through early September.
Spring brings Coromuel Winds to the Bay of La Paz. Caused by the difference in the heating of the air over the Sea of Cortez, land and the Pacific Ocean, the winds represent the Sea of Cortez 'breathing' Rushing inland during the day as the land warms, the air rushes out to Sea, to the northeast at night. Coromuel winds can reach 35kts early in the spring and are appreciated through mid July, as they bring relief after the warm daytime temps. By mid July these winds decrease and eventually disappear, providing still and humid nights by mid August.
Fishing begins to come off winter lows in the Sea by mid March as the water warms up. Even locals can be caught swimming in the Sea by early April, as the water temps climb through the 70's. On the both coasts the night time lows are dictated by the adjacent water temps. Thus the Sea side evenings warm up through the 70's into April. The Pacific side of Baja Sur will continue to see night time temps around 70°F well into June.
Spring also brings Spring Break to Los Cabos. The period has expanded from late February through early April, with the peak in mid-March. The weather in Cabo is usuall. The weather in Cabo is usuall sunny with temps in the mid 80's through the period, getting warmer later in the season.
Summer is hot in Baja, there is no denying that. In Summer you could most aptly divide Baja into East and West. The Pacific keeps the western portion cooler, with winds from the northwest into July. The eastern side of the peninsula warms up quickly as the Sea of Cortez warms. Inland, with no body of water to moderate the temperature highs can reach well over 100° for months at a time and cooling at night is very limited. Thunderstorms are common in July through September.
The past decade has proven that pretty much all of the southern state is susceptible to landfall of a tropical cyclone. The risk period runs from mid August to mid October. Tropical cyclones can brush by Cabo San Lucas and East Cape as early as late July. But the first known landfall of a tropical cyclone in Baja Sur is August 15. Hurricanes and storm spin-off are how the bulk of Baja Sur receives its 7+" of rain per year. Sometimes the entire rainfall of the year will come from one storm, and in just a matter of hours. We have measured rainfall rates in excess of 7" per hour at our weather station.
Baja Sur has seen landfall of only two Major Hurricanes in the last 55 years, Hurricane Kiko in 1989 was the last. There have been over 30 landfalls of lesser storms in the same time period. For the most part, Baja Sur is designed to weather these powerful systems with aplomb. Our Tropical Storms, Category 1 and 2 Hurricanes are powerful and dangerous, but our systems are much smaller in size and ferocity than more famous storms like Katrina in New Orleans. A storm that batters one side of the peninsula may only deliver scattered showers to the other side.
Major hotels and most homes are designed to handle the storms. Streets flood, airports can be closed and power can be knocked out but today, with major road development Baja is rarely stranded without food or fuel (or cerveza) as has happened in the past. If you are visiting Baja during the passage of a tropical cyclone, find a safe place away from the surf and potential flooding of arroyos and take marvel in the power of mother nature. There is no need for panic by you or family members back home. Following a major summer storm you will discover the hidden beauty of Baja as the skies clear to the most beautiful blue and the region blooms green after a good wash-down.
Cabo San Lucas and East Cape are the most often affected areas by our tropical cyclone season. The last few storms to rip into the peninsula chose the western side, crossing the peninsula to the north and emerging in the Sea of Cortez near Loreto. Hurricane Henriette passed west of La Paz in 2007, but is has been since 2006 and Hurricane John since the tip of the peninsula really got a pasting. East Cape has seen the only two landfalls of a Major Hurricane, Paul in 1982 and Kiko in 1989.
Southwest: This is a very popular region of the southern peninsula in summer, as it is cooled by the breezes from the Pacific. But like the north, you don't need to move too far inland to lose that benefit. Todos Santos can maintain temperatures in the upper 80's and low 90's though the hottest time of the year. But just 10 miles inland you could find temps over 100° and time after mid May. Winter storms in the southern hemisphere can bring some great surf to south and southwest facing beaches, as well as shorter period swell generated by Major Hurricanes which move well south of the peninsula through the hurricane season.
Southeast: From San Felipe to La Paz and East Cape it gets hot. The locals run from the intense sun, from shade to shade, as if it were rain. Visiting gringos can get severely burned in minutes waiting for the airport shuttle. Some of the hottest temperatures occur in late June though late July. But pardon the phrase, it is a dry heat. Cooling off in the Sea of Cortez can be a regular daily activity as the waters warm into the 80's. Fishing, is "just of the hook", to confuse metaphors. Temperatures regularly climb close or into triple digits anytime from late May into early October. This season is the most popular with Mexican tourists from the mainland. You must learn to deal with the heat, even in simple chores like going to the store. One learns to rise early and quit before noon. Here is where the old tradition of 'siesta' comes in and many businesses observe the practice of shutting down between 1 and 4PM. Sometimes work can be resumed after 4PM.
Summer in the south slowly becomes more tropical through July. Thunderstorms drift west from the mainland and areas in the Sierra Laguna start to see afternoon rains by early July. But it isn't until mid August that the humidity really kicks in. Thunderstorms can pop up in usual locations every evening from mid July and with increasing intensity though September. Areas like San Bartolo and El Triunfo see thunderstorms with regularity and receive as much as 25" of rain in a season.
As Summer gives way into Fall, the weather influences slide into neutral again. The summer heat begins to break and it is one of the best times to visit anywhere in Baja.
The change of season comes like clockwork in mid October. One morning you wake up and right away, you can sense summer has ended. The humidity drops dramatically one morning, as a High pressure will slip into northeastern Mexico and dry out the entire Eastern Pacific Basin. One of my early hurricane studies was Hurricane Stan. Stan threatened to become one of those rare systems to jump from the Atlantic basin to our Eastern Pacific basin very close to Mazatlan. Had the system reformed it could have delivered a Category 2+ punch to the eastern side of Baja Sur in just hours.
Instead, the strengthening High over southern Texas slipped a little further south and the trail of moisture being drained from Stan by the anti-cyclone High could readily be seen on the satellite image. Stan went from a threat to a memory in about 12hrs.
Hurricane Paul in 2012 came very close to being the latest tropical cyclone to make landfall in Baja Sur. The storm pummeled the western shores from Todos Santos north through to San Ignacio on October 17th. Paul caused a lot of damage to the coastal areas and roadways in central Baja but missed the record books because the system never made landfall as a tropical cyclone. It only passed over a few kilometers of Punto Eugenia and then off into the Pacific again.
Southwest: The region is very pleasant through late December, except for a few very windy days late in the season, as the weather begins to move toward winter. The tropical cyclone threat dissipates by mid October and outdoor activities are top notch until that first winter storm moves into Southern California, then it can get a little windy and damp, although rain could still be weeks away. Late October can still present temps in the mid 80's, but temperatures fall more quickly on the Pacific side, as the ocean cools more rapidly. Daytime highs can remain in the upper 70's well into late December.
Southeast: Here we must extend the definition of this region to include all of the Sea of Cortez side of the peninsula. This is my favorite time of year. You wake up one morning around the 15th of October and before you are out of bed you know the season has changed. The humidity drops dramatically as well as the temperatures fall by 5-7°F as a High pressure moves into northeastern Mexico and Texas. The tropical cyclone threat falls to near 0% by October 15, the latest known landfall in Baja of a tropical cyclone. The Sea of Cortez is still in the mid 80's and diving becomes world class, with visibility sometimes near 100'. The evenings begin to cool off and the air conditioning may get its first rest in 6 months.
The end of the season is marked by that first strong High that moves over the 4 Corners region near the end of November. A 2-5 day blow drops the temperatures and the Sea begins to lose its warmth. Although the region may see temps into the 80's into the Christmas week, fishing and the desire to go swimming in the Sea taper off at the end of November. Every few years Baja Sur will get some showers from tropical moisture moving to the northeast contacting a cold from moving southeast across the peninsula. North winds increase in frequency and intensity through the month of December, landing the region in winter after the holidays.
So with so many climate options you should be able to find your favorite place to play on the Baja peninsula, almost any time of year.