Average Frost Dates
Our average first frost date is just that—an average—so it’s a good idea to familiarize yourself with the norms for your area and plan accordingly. Frosts can occur much earlier or later than typical.
Average Frost Dates
Our average first frost date is just that—an average—so it’s a good idea to familiarize yourself with the norms for your area and plan accordingly. Frosts can occur much earlier or later than typical.
There are a number of factors that contribute to frost, and temperatures can vary by neighborhood or even block to block. For example, the average first frost in downtown Portland is typically three weeks after the first frost at the Portland Airport. In outlying areas like Canby and Forest Grove, the average first frost is usually in mid-October.
Statistics used to formulate first and last frost dates are drawn from weather data collected from 1981-2010. All data is collected at low elevations. Chart source info is from the Oregon Climate Service at OSU.
| City | Average First Frost/Last Frost |
| Beaverton | November 2/April 14 |
| Canby | October 30/May 1 |
| Forest Grove | October 19/April 26 |
| Hillsboro | October 23/April 26 |
| Newberg | November 20/April 6 |
| Oregon City | November 6/April 3 |
| Portland Airport | November 6/March 28 |
| Portland Downtown | November 27/February 24 |
| Troutdale | November 8/March 28 |
| Wilsonville | October 30/April 18 |
Pre-Front Preperation
Before frosts arrive, tend to a few tasks:
- Bring houseplants and frost-tender plants inside. Examine plants closely, looking for slugs and pesky insects and insect eggs. Remove, wash off, or apply insecticides if needed.
- Harvest the last of your warm-season fruits and veggies. Tomatoes, summer squash, eggplant, peppers, cucumbers, potatoes, fall raspberries, ripe apples, and pears should be harvested. Install season-extenders in your vegetable garden. Cloches, row cover, and cold frames can all be used to protect fall veggies from frost or heavy rain while elevating temperature. Read more about Fall and Winter Vegetable Gardening in the Pacific Northwest.
- Sow cover crops.
- Plant spring bulbs! Many bulbs like tulips and daffodils can be planted after frosts, but should be in the ground before soil is saturated or frozen. October is the perfect month.
- Protect geraniums and tender fuchsias. Prune branches down to about 6”, remove thin wispy branches entirely, remove any slugs or aphids that are present, and store in a cool dark space for winter (temp should not be below 40°F). Here’s a helpful walkthrough from the Oregon Fuchsia Society.
Other Fall and Winter Garden Help
You can also find helpful tips for preparing your garden for the winter on our Winter Preparation page.
The fall is a great time to improve your soil. Read more about fall mulching.
