Where do I find my frost dates?

Your cooperative extension office, a planting-zone lookup, or long-term local weather records. Enter the typical dates for your exact area - frost varies street by street in hilly country.

Are frost dates guaranteed?

No - they are usually the 50% probability point from historical records. For tender crops, many gardeners wait an extra week or two after the published date.

Why 6 and 8 weeks for seed starting?

Those are the standard indoor lead times: slow warm-season crops like tomatoes and peppers need about 8 weeks to transplant size; faster crops like brassicas need about 6.

Can I extend the season past the frost dates?

Yes - row covers, cold frames and low tunnels typically buy 2-4 weeks at each end of the window.

Frost Date Calculator - gardencalculator.net

🌱 Grow a Garden Calculator

Enter your local last spring and first fall frost dates to get the days remaining, your growing-season length and indoor seed-starting dates.

Written by Jude Ramsey · Last updated August 2026

How it works

Frost dates are local — look yours up from your cooperative extension office or a planting-zone map, then enter them here. The calculator returns the countdown to your last spring frost, the length of your frost-free growing season, and the two dates gardeners actually plan around: 8 weeks before last frost (start tomatoes and peppers indoors) and 6 weeks before (start brassicas and many annual flowers).

Worked example

With a last frost of 5 May and a first fall frost of 10 October, the season runs 158 days — long enough for nearly any vegetable. Tomato seeds would start indoors around 10 March, cabbage around 24 March.

Reading the dates sensibly

A published frost date is a probability, not a promise — typically the 50% chance point. Tender crops appreciate a one-to-two-week buffer after it, and season-extending covers can bend both ends of the window. Everything runs in your browser; nothing is stored.

August 18, 2026