Frost Dates for Johnstown, PA 15904

Johnstown has 6 ZIP codes. The Johnstown, PA frost page lists all of them with their dates.

Last spring frost May 11 · First fall frost October 9 · 151 frost-free days · USDA Zone 6b

Frost probability for 15904

Frost10%50%90%
Spring (last frost)May 26May 11April 26
Fall (first frost)September 25October 9October 24

Dates come from NOAA 1971–2000 freeze probabilities at the nearest reporting station (39.9 km away); the 50% date is the median year.

Month by month in Johnstown

MonthWhat to do
JanuaryPlan your garden layout and order seeds. Research varieties suited to your frost dates.
FebruaryStart the slowest-growing crops indoors: onions, leeks, and celery (10–12 weeks before last frost).
MarchStart peppers and eggplant indoors 8–10 weeks before your last frost (around May 11). Start tomatoes about two weeks later, 6–8 weeks before last frost.
AprilStart herbs, basil, and squash indoors (4–6 weeks before frost). Direct sow peas, spinach, and lettuce if soil is workable.
MayLast frost around May 11. Transplant cold-hardy crops (broccoli, kale, cabbage). Harden off tomato and pepper seedlings.
JuneFrost has passed. Transplant tomatoes, peppers, and basil outdoors. Direct sow beans, cucumbers, squash, and zucchini.
JulySuccession plant lettuce and greens. Keep beds weeded and watered consistently.
AugustHarvest regularly to encourage production. Monitor for pests and disease.
SeptemberFirst fall frost approaching (around October 9). Transplant fall brassicas. Sow spinach, arugula, and radishes.
OctoberFirst frost around October 9. Harvest tomatoes and peppers before frost. Cover cold-hardy crops with row covers to extend the season.
NovemberHarvest remaining cold-hardy crops: kale, carrots, and beets. Plant garlic bulbs for next year.
DecemberClean up spent plants. Add compost to beds. Rest, review, and plan next year's garden.

What grows in a 151-day season

Frequently Asked Questions

What is the last frost date for Johnstown, PA (ZIP 15904)?

The median last spring frost date for Johnstown, PA (ZIP code 15904) is around May 11. This is the 50th-percentile date — meaning half of all years see frost end before this date. Use the 10% and 90% dates to understand the full range of risk in your area.

What is the first fall frost date in Johnstown, PA?

The median first fall frost date for Johnstown, PA is around October 9. Plan to harvest or protect frost-sensitive crops like tomatoes and peppers at least a week before this date to avoid losses.

How long is the growing season in Johnstown, PA?

The frost-free growing season in Johnstown is about 151 days. This window — from your last spring frost to your first fall frost — is when warm-season vegetables thrive. Cold-hardy crops like kale, spinach, and peas can extend your season by weeks on either side.

What USDA hardiness zone is Johnstown, PA?

Based on frost date patterns, Johnstown falls approximately in 6b. USDA hardiness zones are determined by average annual minimum winter temperatures and guide both plant selection and planting timing for your location.

When should I start tomatoes indoors in Johnstown, PA?

Start tomato seeds indoors 6–8 weeks before your last frost date (around May 11). For Johnstown, that's roughly March 16 to March 30. Transplant outdoors 1–2 weeks after your last frost.

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