ロサンゼルスの月別の天気

The city enjoys a temperate Mediterranean climate most of the year. However, the climate of Southern California is somewhat complex and temperatures can fluctuate wildly depending where you are in the city, since the varied terrain results in a series of microclimates. On the same day, daytime highs can vary by as much as twenty degrees Fahrenheit between coastal locations and cities in the San Fernando and San Gabriel Valleys. The coast tends to stay a bit cooler, which helps with the summer heat, but as such is also chillier at night. Bring a sweater and pants if you stay for dinner near the coast, even in the summer. Summers are warm, occasionally hot, and bring the infamous dirty smog, though the air quality has significantly improved over the years. In August and September, the hottest months, average daytime highs in Downtown Los Angeles are 83°F (28°C) and nighttime lows average 63°F (17°C).…

LA forum threads describe January as genuinely variable, with average highs around 65F but real swings possible from the 50s up toward 80F depending on the week - posters described three days of rain followed by a week of sun as entirely normal rather than unusual. Layering was the universal packing advice given how much the day-to-night and coast-to-inland temperature swing can be. Ocean water was described as too cold for swimming without a wetsuit and beach lounging generally isn't realistic this time of year, even on a warm, sunny day - the coast and the inland valleys can also run noticeably different from each other on the same day.

LA forum regulars describe March as a coin flip rather than the reliable sun the city is known for: it's “towards the end of our rainy season,” so “if it's not raining it can be clear, cool, sunny and spectacular” — but a sweater for evenings is standard advice either way. The clearest warning is about the beach, not the city: “March is not beach weather... water too cold, air temps tend to be cooler too.” What March buys instead is the trade every poster mentions: “less expensive, less crowded” than the summer crush. Our record: 20.4°C days but only 8.1°C nights, 8.4 rain days and a 13.6°C sea — fine for a quick dip, not for lounging.

Asked whether mid-April is beach weather here, regulars split the question: the sand yes, the water no. Our sea column is why - 14.7C, which is swimming for the committed and paddling for everyone else, under air of 24.2C. They also warn that the coast and the inland city are different places on the same day, the beach in the low seventies while Hollywood is in the eighties, so the decision about a sweater is made by geography rather than forecast. Rain has effectively stopped, 15.9mm across 1.9 days, with 11.5 hours of sun. Nights fall to 12.9C, which surprises people. The record: humidity 61 percent, a dew point of 8.3C, a 14.9 kph wind and AQI 79.

Los Angeles-forum threads on 'May Gray' describe a coastal-only phenomenon: morning low cloud and fog that can keep the beach socked in past midday, while neighborhoods five miles inland sit under blue sky and run 10-20 degrees warmer at the same hour. Regulars call it a legitimate pattern but say it barely changes anyone's plans - people still walk the boardwalk and play volleyball through it, and it typically burns off by early afternoon. May's record backs the two-zone read: 23.8C days, 14.2C nights, almost no precipitation at under two days, 12.1 hours of sun and a 16.7C sea still on the cool side of comfortable.

June gloom is a daily timetable rather than a season. The marine layer forms offshore, sits over the coast at breakfast, burns off through the late morning, and marches back in from the ocean about five - and the beaches are the last to clear, sometimes not at all. A few blocks inland can be five to fifteen degrees warmer on the same afternoon, which is why downtown barely notices it. Our row averages the whole basin at 27.7C reading as 29C with 13.1 hours of sun, and the number that matters at the coast is a 17.5C sea. Rain has stopped, 1.8mm in the month. The record: humidity 59 percent, a dew point of 13.3C, a 13.8 kph wind and AQI 56.

September is Los Angeles's hottest month, and the forum's advice is mostly about where you stand in it: near the ocean it stays mild, while the inland valleys run far hotter and a Santa Ana heat wave can push them past 40°C. Early September often pairs the heat with humidity; regulars say that usually eases later in the month, leaving late September and October sunny and pleasant. Their most practical tip is scheduling — don't do the uphill walk to Universal between 11 and 3.