Weather in San Jose in April

Prime time. April is about as good as San Jose gets. Highs average 20 °C, lows 7.8 °C, and rain falls on 6 days — nothing in the month is working against you.

April ranks 4 of 12 in San Jose: past the worst of the year but short of May, which is the month to book if the dates are open.

Rain falls on only 6 days, so an itinerary with no wet-weather fallback is a reasonable risk. Nothing specialised needed — this is the month you pack for the trip rather than for the weather.

What the averages hide

The averages here are honest — no hidden extremes worth planning around. Across the twenty years measured, the hottest April day reached 34.5 °C and the coldest night fell to 1.8 °C, and the wettest single day dropped 27 mm — roughly 68% of the month's rain in one day.

April is moderately variable: 3 mm in the driest year against 101 mm in the wettest, around an average of 40 mm. Roughly two Aprils in three land near that average, and the third does something else entirely.

Wind is light at 7.7 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 78%, high enough to notice on the warm days without dominating them.

How April sits in the year

The month is on the way up: 1.9 °C warmer than March, and May adds another 3.6 °C. Late in the month feels noticeably different from the start of it, which is worth knowing if the trip is short.

Daylight in April

13.1 hours of daylight, gaining 1.1 hours across the month. That is between San Jose's extremes of 14.7 and 9.6 hours, so days are long enough not to constrain the plan.

Sea temperature

The sea sits at about 12.3 °C in April — too cold to swim without a wetsuit. The sea peaks at 15.4 °C in September and bottoms out at 12.3 °C — water lags the air by a month or two, which is why the best swimming often comes after the best weather.

How busy it gets

Busy. Popular without being frantic; book the things you care about, improvise the rest.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

April in San Jose versus nearby

If San Jose is one option among several, the nearby comparison is worth making. San Francisco is close enough to be a coin toss — 2.6 °C cooler, the same number of rain days. Napa is close enough to be a coin toss — within a degree on temperature, the same number of rain days.

So: April is effectively as good as it gets here — 6 points behind May, which is inside the margin where the weather stops being the deciding factor and price starts being it.

Every month in San Jose

See all twelve months in San Jose, or where else to go in April.