One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The best time to plant cosmos in Half Moon Bay can be estimated by using the USDA zone info.

Planting Calendar for Cosmos

Frost tolerance for cosmos:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since cosmos do ok in moderate cold you can plant them a bit earlier in the year than other frost tender plants.

The earliest that you can plant cosmos in Half Moon Bay 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 cosmos and expect a good harvest is probably September. Any later than that and your cosmos may not have a chance to really do well. Starting your cosmos indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Half Moon Bay the average date of last frost happens on January 31. It might get as low as 30°F during the coldest months of winter.

Since the USDA zone info for Half Moon Bay is not always accurate the actual date of last frost changes from year to year. Half of the time in Half Moon Bay last frost occurs after January 31 so just be sure to be ready to cover your cosmos if you have a surprise late frost.

USDA Zone Info for Half Moon Bay

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 Half Moon Bay

You may be interested in your other planting guides for Half Moon Bay.