Weather in Napa in July

A good month. July is a solid month to be in Napa. Highs average 33.9 °C, lows 15.4 °C, and rain falls on 0 days — nothing in the month is working against you.

July ranks 8 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 is not a factor worth planning around this month. Pack for 33.9 °C days and 15.4 °C nights; the spread matters more here than any single number.

What the averages hide

Averages flatten a month, and this one hides a few things: 12 days clear 35 °C, so a serious heatwave is normal rather than notable; the day swings 18.5 °C from low to high, which means one bag has to cover both. Across the twenty years measured, the hottest July day reached 44.7 °C and the coldest night fell to 10.8 °C.

July is dependably dry, and that reliability is the point: across the twenty years measured, the wettest July on record still only managed 10 mm, and the driest managed 0 mm. There is no meaningful variability to plan around, which makes this one of the few months anywhere that you can build a fixed outdoor itinerary against without a fallback. The wettest single day in twenty years of Julys brought 4 mm. Rain simply is not the variable that decides this trip — heat, crowds and cost are.

Wind is light at 6.7 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 49%.

How July sits in the year

Temperatures hold steady either side: 30.5 °C in June, 33.9 here, 33.8 in August. Nothing about the timing within the month matters much.

Daylight in July

July is at or near the longest days of Napa's year: 14.6 hours of daylight, losing 0.6 hours across the month. Evenings are the real gain — dinner outdoors still happens in full light.

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. Within July itself the daily swing is 18.5 °C, so mornings and afternoons need different clothes.

How busy it gets

Shoulder. The value months — prices ease off and you get the place closer to itself.

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

July in Napa versus nearby

If Napa is one option among several, the nearby comparison is worth making. San Francisco is a better bet in July — 11.1 °C cooler, the same number of rain days. Sacramento is the weaker option in July — 3.7 °C warmer, the same number of rain days.

So: July is a compromise. May is 25 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 July.