Weather in Napa in March

A good month. March is a solid month to be in Napa. Highs average 17.8 °C, lows 7 °C, and rain falls on 10 days — nothing in the month is working against you.

March ranks 7 of 12 in Napa: past the worst of the year but short of May, which is the month to book if the dates are open.

Rain on 10 days, 4 of them heavy. Enough to need a plan B, not enough to need a plan around it. Pack for 17.8 °C days and 7 °C nights; the spread matters more here than any single number.

What the averages hide

The averages here are honest — no hidden extremes worth planning around. Across the twenty years measured, the hottest March day reached 26.3 °C and the coldest night fell to -0.5 °C, and the wettest single day dropped 53 mm — roughly 55% of the month's rain in one day.

March is moderately variable: 5 mm in the driest year against 240 mm in the wettest, around an average of 97 mm. Roughly two Marchs in three land near that average, and the third does something else entirely.

Wind is light at 5.7 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 81%, high enough to notice on the warm days without dominating them.

How March sits in the year

The month is on the way up: 2 °C warmer than February, and April adds another 2.4 °C. Late in the month feels noticeably different from the start of it, which is worth knowing if the trip is short.

Daylight in March

11.9 hours of daylight, gaining 1.2 hours across the month. That is between Napa's extremes of 14.8 and 9.5 hours, so days are long enough not to constrain the plan.

An inland climate

With no coast nearby, the year swings a fair way — 28.6 °C between the warmest afternoons and the coldest nights, wider than any coastal city at this latitude would manage.

How busy it gets

Quiet. Few other visitors, cheaper rooms, and a real chance some seasonal operators are shut.

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

March in Napa versus nearby

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

So: March is a compromise. May is 23 points better and is what Napa is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in Napa

See all twelve months in Napa, or where else to go in March.