Frost dates for Altoona Blair Co Ap, Pennsylvania
Half of years have their last spring frost by April 23 — but 1 year in 10 still frosts after May 11.
Every other site gives you one date. A frost date is not a date: it is a percentile from 30 years of records at a nearby weather station, and planting to the median means losing the crop in half of years. Both numbers are below, so you can choose the risk yourself.
The odds
Last spring frost
- Frost this late in 1 year in 10
- May 11
- 1 year in 5
- May 5
- 3 years in 10
- April 30
- 2 years in 5
- April 27
- Half of years (the median)
- April 23
First fall freeze
- Freeze this early in 1 year in 10
- October 5
- 1 year in 5
- October 11
- 3 years in 10
- October 14
- 2 years in 5
- October 18
- Half of years (the median)
- October 21
- Growing season
- about 177 days
- Hardiness zones nearby
- 6b, 7a
Where these numbers come from
NOAA NCEI 1991–2020 Climate Normals, station Altoona Blair Co Ap (USW00014736), at 40.30, -78.32. These are that station's own records, unshifted. The further your garden is from it, the less exactly they describe your ground — the planner resolves the nearest station to your own ZIP and lowers its confidence with distance, rather than presenting one number as if it were measured in your yard.
Cold air also pools in low ground on the clear, still nights when frost happens, so a hollow can freeze while a slope a hundred metres away does not. No table can know that about your garden. Your own logged frosts eventually can.
ZIP codes nearest this station
15533, 15536, 15537, 16621, 16622, 16623, 16625, 16631, 16633, 16634, 16635, 16637, 16638, 16647, 16648, 16650, 16655, 16657, 16659, 16662, 16664, 16665, 16667, 16670, 16672, 16673, 16674, 16678, 16679, 16682, 16685, 16689, 16691, 16693, 16694, 16695, 17052, 17066, 17075, 17228, 17229, 17249, 17253, 17260, 17264.
What can I plant here, and when? →
Nearby stations
The nearest stations, and how their last-frost dates compare — the frost gradient across your area, which no single station shows.
- Johnstown Cambria Co Ap, PA — last frost by April 29
- Prince Gallitzin Sp, PA — last frost by May 10
- Philipsburg 2 S, PA — last frost by May 13
- State College Hcn, PA — last frost by April 20
- Shippensburg, PA — last frost by April 19
- Laurel Mtn, PA — last frost by April 26
Other stations in Pennsylvania.
- Carlisle Wtp, PA — last frost by April 23
- Confluence 1 Sw Dam, PA — last frost by April 30
- Putneyville 2 Se Dam, PA — last frost by May 10
- Schenley Lock, PA — last frost by April 21
- Mckeesport, PA — last frost by May 2
- Middletown Harrisburg Intl Ap, PA — last frost by April 9
- Selinsgrove 2 S Hcn, PA — last frost by April 25
- Washington 3 Ne, PA — last frost by April 24