One of the first steps you take when you are figuring out your gardening schedule is find your 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.

A common way of figuring out when it's a good idea to plant watermelon is to use the USDA zone info for San Dimas.

Planting Calendar for Watermelon

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

It's probably not a good idea to plant watermelon until after the last frost when the weather gets warmer because they do not do well in cold weather.

The earliest that you can plant watermelon in San Dimas 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 really do well. If you are starting your watermelon indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In San Dimas the average date of last frost happens on January 31. In the coldest months of winter you should expect an average low temperature of 30°F.

It's important to remember that the actual date of last frost is just an average because it is based on the USDA zone info for San Dimas and it changes from year to year. Half of the time in San Dimas there is a last frost after January 31 so always be ready to cover your watermelon in the event of a surprise late frost.

USDA Zone Info for San Dimas

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 Dimas

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