Your nature year
Allentown, Pennsylvaniathrough the year
Also for Bethlehem, PA, Easton, PA: the same nearby places.
When do frost, green-up and fall color come to Allentown?
Delaware Water Gap, 32 miles from Allentown, is the nearest fall foliage spot on this site, usually well under way by late October (statewide). Bombay Hook (92 mi) is the pick for wildflowers, Apr 1–May 31 (local timing). The town is about 295 feet above sea level. Expect about 187 frost-free days in Allentown: the last spring frost usually comes around Apr 20, the first fall one around Oct 24, going by NOAA's Allentown Lehigh Vly International Airport station 4.2 miles away. About 4 weeks pass between first leaf and first bloom here. The USA-NPN spring index puts first leaf here around Mar 30 and first bloom around Apr 29. Head northeast for the closest of the 24 places we follow around Allentown. Across Pennsylvania, fall color is usually well under way by late October.
Updated Sep 28. Sources: US Census Bureau, 2024 Gazetteer (places) ↗ (opens in a new tab), US Census Bureau, city and town population estimates, 2024 ↗ (opens in a new tab), NOAA NCEI U.S. Climate Normals 1991–2020 (annual/seasonal) ↗ (opens in a new tab)
Allentown's year at a glance
- Frost possible
- Frost-free, ~Apr 20 to ~Oct 24
- First leaf ~Mar 30
- First bloom ~Apr 29
- Fall color under way ~Oct 25 (PA)
- Today
Near Allentown right now
- Fall color is usually well under way by late October in PennsylvaniaStatewide · USA-NPN volunteer observations, 2020–2025 · not a forecast~4 weeks
- First fall frost usually around Oct 24 · last spring frost around Apr 20NOAA 1991–2020 normals, Allentown Lehigh Vly International Airport (4.2 mi, 50% dates)~4 weeks
- Kenilworth Aquatic Gardens · 140 mi · Local timing: May 21–Sep 30Wildflowers · in its window now
- Fall foliage · Delaware Water Gap · 32 miStatewide: usually well under way by late October~3 weeks
Allentown's nature year
- Cherry blossoms · Baltimore (Fort McHenry)Mar–Apr
- Spring green-upMar
- Wildflowers · Bombay HookApr–May
- Last spring frostApr
- Tulips · Washington, DCApr
- Fall color (PA)Oct
- First fall frostOct
Nearby, season by season
Cherry blossoms
- Baltimore (Fort McHenry) · 108 miusually Mar 24–Apr 7~6 months
- US National Arboretum · 141 miusually Mar 1–Apr 30~5 months
- Washington, DC · 144 miusually Mar 25–Apr 7~6 months
Fall foliage
- Delaware Water Gap · 32 miStatewide: usually well under way by late October~3 weeks
- Cherry Valley Refuge · 33 miusually Oct 21–31~3 weeks
- New York City · 80 miStatewide: usually well under way by mid-October~3 weeks
Tulips
- Washington, DC · 144 miLocal timing: Apr 1–20~6 months
Wildflowers
- Bombay Hook · 92 miLocal timing: Apr 1–May 31~6 months
- Catoctin Mountain · 122 miLocal timing: Apr 1–May 31~6 months
- Kenilworth Aquatic Gardens · 140 miLocal timing: May 21–Sep 30
Snow in Allentown
Snow usually becomes possible around Dec 21 (our calculation from NOAA's daily snow chances: the first day the chance of 0.1" or more of snow reaches 10%). NOAA's normals at Allentown Lehigh Vly International Airport (4.2 mi away): 33 inches of snow in an average year, about 8.1 days with 1 inch or more.
NOAA's chance of at least 0.1 inch of snow on each date (one value per week, September to May), averaged over 1991–2020. A typical year, not a forecast.
Frost and green-up
Last spring frost
Apr 20
Average (50% date)
First fall frost
Oct 24
About 187 days without frost between
Spring green-up
Mar 30
First bloom around Apr 29
Frost: NOAA 1991–2020 climate normals at Allentown Lehigh Vly International Airport (4.2 mi from Allentown), the day a 32 °F night is as likely as not. Green-up: the USA-NPN Spring Index, 1991–2020 average at the town.
Questions people ask
When is the first frost in Allentown?
On average around Oct 24, and the last spring frost around Apr 20: about 187 days without frost between. These are NOAA's 1991–2020 normals at Allentown Lehigh Vly International Airport, 4.2 miles away (the day a 32 °F night is as likely as not).
When does spring green-up reach Allentown?
The USA-NPN Spring Index puts first leaf around Mar 30 and first bloom around Apr 29, on average for 1991–2020 at the town.
Where can I see cherry blossoms near Allentown?
Baltimore (Fort McHenry), 108 miles (usually Mar 24–Apr 7); US National Arboretum, 141 miles (usually Mar 1–Apr 30); Washington, DC, 144 miles (usually Mar 25–Apr 7). Distances are straight-line.
Where can I see fall foliage near Allentown?
Delaware Water Gap, 32 miles (statewide: usually well under way by late October); Cherry Valley Refuge, 33 miles (usually Oct 21–31); New York City, 80 miles (statewide: usually well under way by mid-October). Distances are straight-line.
When does it start snowing in Allentown?
Snow usually becomes possible around Dec 21: our calculation from NOAA's daily snow chances: the first day the chance of 0.1" or more of snow reaches 10%, at Allentown Lehigh Vly International Airport. An average year brings 33 inches (NOAA 1991–2020). A typical year, not a forecast.Sources: NOAA NCEI U.S. Climate Normals 1991–2020 (annual/seasonal snowfall) ↗ (opens in a new tab), NOAA NCEI U.S. Climate Normals 1991–2020 (daily snowfall probabilities) ↗ (opens in a new tab)
How we know
US Census Bureau, 2024 Gazetteer (places) (opens in a new tab) (Sep 27) · US Census Bureau, city and town population estimates, 2024 (opens in a new tab) (Sep 27) · NOAA NCEI U.S. Climate Normals 1991–2020 (annual/seasonal) (opens in a new tab) (Sep 27) · USA National Phenology Network, Spring Index 1991–2020 averages (opens in a new tab) (Sep 27) · USA National Phenology Network, colored leaves observations (opens in a new tab) (Sep 28)