The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's a good idea to figure out when it's possible to plant watermelon by referring to the USDA zone info for San Francisco.

Planting Calendar for Watermelon

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

It's probably a bad idea to plant watermelon until after the last frost has passed because they are not cold tolerant.

The earliest that you can plant watermelon in San Francisco 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. You probably don't want to wait any later than that or else your watermelon may not have a chance to really do well. If you are starting your watermelon indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In San Francisco the average date of last frost happens on January 31. You should expect an average low temperature of 35°F in the coldest months of winter.

Remember that USDA zone info for San Francisco is an average and the actual date of last frost is different every year. Half of the time in San Francisco it frosts late in the year after January 31 so make sure that you are ready to protect your watermelon if you have a late frost.

USDA Zone Info for San Francisco

Here is the info for USDA Zone 10b.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	35°F
Highest Expected Low	40°F

This means that on a really cold year, the coldest it will get is 35°F. On most years you should be prepared to experience lows near 40°F.

Plants to Grow in San Francisco

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