One of the best tools that you have as gardeners to help us estimate 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.

A way of making a decision about when it's possible to plant dahlia is to consult the USDA zone info for San Rafael.

Planting Calendar for Dahlia

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

It's not a good idea to plant dahlia until after the last frost because they do not do well in cold weather.

The earliest that you can plant dahlia in San Rafael 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 dahlia and expect a good harvest is probably September. Any later than that and your dahlia may not have a chance to really do well. Starting your dahlia indoors is a great way to get them started a little bit earlier.

Last Frost Date

In San Rafael the average date of last frost happens on January 31. You can expect an average low temperature of 30°F in the coldest months of winter.

Since the USDA zone info for San Rafael is an average the actual date of last frost is different every year. Since half of the time in San Rafael there is a last frost after January 31 be ready to protect your dahlia in the event of a late frost.

USDA Zone Info for San Rafael

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 Rafael

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