One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

It's possible to estimate when it's the best time to plant watermelon by using the USDA zone info for San Bruno.

Planting Calendar for Watermelon

Frost tolerance for watermelon:	Not tolerant of frost.
When to plant:	After the last frost.

Since watermelon are not cold tolerant you need to wait until after the last frost has passed before you can plant them.

The earliest that you can plant watermelon in San Bruno is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant watermelon and expect a good harvest is probably September. If you wait any later than that and your watermelon may not have a chance to grow to maturity. You can get started a little bit earlier by starting your watermelon indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on January 31 in San Bruno. It might get as low as 30°F during the coldest months of winter.

Since the USDA zone info for San Bruno is not always accurate the actual date of last frost changes from year to year. Half of the time in San Bruno you get surprised by a frost after January 31 so be sure to be ready to protect your watermelon in the event of a surprise late frost.

USDA Zone Info for San Bruno

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in San Bruno

You may be interested in your other planting guides for San Bruno.