Ottawa residents woke up to a frost warning this week as Environment and Climate Change Canada issued a yellow frost advisory for eastern Ontario and western Quebec — a timely reminder that spring in the capital still comes with some cold teeth.
What the Advisory Covers
The yellow frost advisory affects a broad swath of the region, stretching across eastern Ontario — including Ottawa and its surrounding communities — as well as parts of western Quebec just across the river. Yellow advisories indicate that frost is likely, with overnight temperatures expected to dip to or below 0°C.
These kinds of advisories are common in May across the Ottawa Valley, where cold snaps can arrive even after stretches of warm, sunny weather have lulled gardeners into a false sense of seasonal security.
What It Means for Ottawans
If you've already put out your tomatoes, peppers, basil, or other frost-sensitive plants, now is the time to bring them back inside or cover them overnight. A single hard frost can wipe out weeks of seedling progress in a matter of hours.
Farmers and market gardeners in the Greenbelt and rural areas east of Ottawa — including parts of Russell, Prescott, and Glengarry counties — are particularly affected. Early-season crops like lettuce and spinach can handle light frost, but anything tender needs protection.
For homeowners, it's also worth covering any ornamental plants or early-blooming flowers that may have pushed through in the warmer days prior.
Ottawa's Frost-Prone Spring
Ottawa's last average frost date falls around mid-May, which means this advisory — while frustrating — is well within the normal range for the region. The Ottawa Valley's geography, nestled between the Canadian Shield and the St. Lawrence Lowlands, makes it particularly susceptible to cold air drainage overnight.
Environment Canada recommends monitoring its weather alerts closely during this period, as conditions can change quickly. The WeatherCAN app and the Environment Canada website are the most up-to-date sources for advisory status.
Tips to Protect Your Garden
Here are a few quick steps Ottawa gardeners can take during a frost advisory:
- Cover plants with old bedsheets, frost cloth, or even cardboard boxes before sunset — trapping daytime warmth helps overnight.
- Water the soil (not leaves) in the afternoon. Moist soil retains heat better than dry soil.
- Bring in containers — potted plants are far more vulnerable than those in the ground.
- Hold off transplanting new seedlings outdoors until the advisory lifts and overnight lows are consistently above 5°C.
The good news? Frost advisories are typically short-lived, and warmer, more settled spring weather is usually just around the corner.
Stay Updated
Keep an eye on Environment Canada's weather alerts for Ottawa and the surrounding region as conditions evolve this week. For the latest on local weather advisories, check the Environment Canada website or the WeatherCAN app.
Source: CBC News / Google News Ottawa RSS feed
