Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The earliest that you can plant watermelon in Diamond Bar should be determined by using the USDA zone info.

Planting Calendar for Watermelon

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

Watermelon do not do well in cold weather which tells us that you really should wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant watermelon in Diamond Bar 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. Any later than that and your watermelon may not have a chance to grow to maturity. Starting your watermelon indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Diamond Bar the average date of last frost happens on January 31. In the coldest months of winter you can expect an average low temperature of 30°F.

Always keep in mind that USDA zone info for Diamond Bar is not always accurate and the actual date of last frost changes from year to year. Half of the time in Diamond Bar last frost occurs after January 31 so make sure that you are ready to protect your watermelon if you have a surprise late frost.

USDA Zone Info for Diamond Bar

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 Diamond Bar

You may be interested in your other planting guides for Diamond Bar.