Climate in Channel Islands (California)

The climate of the Channel Islands is mild oceanic, with mild winters and cool summers. The rains are scarce and concentrated from November to March. The wind can blow moderate or strong, during periods of bad weather in winter, while in the rest of the year, the north-west wind blowing on the ocean is frequent.
The islands are located off the southern coast of California, at 32-34 degrees north latitude, and are divided into two groups: the northern islands (Anacapa, San Miguel, Santa Cruz, Santa Rosa) and the southern islands (San Clemente, San Nicolas, Santa Barbara, Santa Catalina).
Five of the eight islands that comprise the archipelago (the northern ones plus Santa Barbara) are part of the Channel Islands National Park.
The Channel Islands are called "the Galápagos of California" because they have some characteristics in common: they are also arid, in some periods they are cool and misty, and they are inhabited by species that have evolved independently.
In the interior of the islands, there are trails, which climb the hills, generally of modest height. The highest hill is Devils Peak, 754 meters (2,474 feet) high, on the island of Santa Cruz. From the headlands, you can watch whales, while from the boats you can observe dolphins, seals and sea lions. You can go kayaking in the caves, or snorkeling in the forests of giant algae. The islands are inhabited by native species of foxes and sea birds.
Winter is mild, with periods of bad weather but also sunny periods.
On the coldest nights of the year, the temperature generally reaches 4/5 °C (39/41 °F). The cold records are around 2 °C (35.5 °F).
In summer, there are cool, spring-like periods, especially in June and July, and pleasantly warm periods, especially in August and September. The islands are so cool even in summer because of the cold current that flows in the ocean off California. The cold current also causes fogs and cloudy skies, especially in spring and summer (with a maximum in May and June). However, the amount of sunshine in the islands is quite good, especially in winter when, apart from bad weather periods, the sky is often clear.
Even though the summer is normally cool, the temperature can exceed 30 °C (86 °F) when the hot wind blows from the deserts of Nevada (the wind called Santa Ana, which arrives usually weakened in these islands). This can also happen in the fall.
In July 2018, the temperature reached 41 °C (106 °F) in Santa Catalina and 39 °C (102 °F) in San Nicholas, while in September 2020, it reached 43.3 °C (110 °F) in Santa Catalina.



At the airport of Santa Catalina Island, located at 490 meters (1,600 feet) above sea level, the average temperature of the coldest month (February) is of 12.6 °C (54.7 °F), that of the warmest months (August and September) is of 21.4 °C (70.6 °F). At sea level, daytime temperatures are a bit lower in summer, around 22-23 °C (71/73 °F) from July to September, so the cold ocean creates thermal inversion conditions. Here are the average temperatures.

Precipitation amounts to 325 millimeters (12.8 inches) per year: it is therefore scarce. It ranges from 0 mm (0 in) in the driest months (July, August) to 75 mm (3 in) in the wettest (January). Here is the average precipitation.

The sea on the Channel Islands is cold even in summer due to the aforementioned cold current. Here are the average sea temperatures in Anacapa, the island closest to the mainland, located 20 km (12 miles) away from the city of Oxnard.

In the southern islands, the sea is a little warmer: in San Clemente, the ocean temperature ranges from 15 °C (59 °F) from January to March, to 20 °C (68 °F) in August and September.

Best time

The Channel Islands can be visited all year round, but in winter, there can be bad weather periods, with wind and rain. You can therefore choose the period that goes from April to October. In spring, the landscape is in bloom, however, in May and June, fog and clouds are more frequent. However, there are species that bloom even in winter and summer.
Even in summer, it can be useful to bring a sweatshirt and a windbreaker. Even if the temperature is generally not high, the sun is strong, so it may be useful to bring a sun hat and sunscreen.