Photo: Mr. Matté (if there is an issue with this image, contact me using this image's Commons talk page, my Commons user talk page, or my English Wikipedia user talk page; I'll know about it a lot faster) · CC BY-SA 4.0For weather, Petersburg is about as ordinary as U.S. towns get
On a normal January night the air cools to about 20°. Expect the heaviest rain or snow in September and the lightest in February. From May to June and August to October, highs of 64–83° make it easy to spend the day outdoors.
A year in Petersburg at a glance
Each month’s typical high and low, and what it brings.
What stands out about Petersburg’s climate
Compared with towns across the U.S., with Petersburg’s place in Pennsylvania beside it.
What a year in Petersburg feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 191 frost-free days a year
In half of years the last 32° night comes by April 19 and the first by October 28. Frost and day counts come from NOAA’s station at Raystown Lake 2, PA, 13 miles from the town’s center, 290 ft higher.
The 2023 USDA map puts Petersburg’s center in zone 6b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −1°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 26 inches of snow a winter
Snow, measured at Williamsburg, PA, is heaviest from January through February, about 7 inches a month. Precipitation (rain plus melted snow) adds up to 41 inches a year; September is the wettest month and February the driest. Rain or snow falls on about 136 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Petersburg
87% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through April.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Raystown Lake 2, PA.
Living with Petersburg’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
191 frost-free days in zone 6b. The last frost comes by Apr 19 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Oct 28.
Months with highs of 62–84° and lows of 40° or more: May, June, August, September and October. 0.0 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Petersburg from natural hazards, river flooding is the largest share (83%); heat waves, cold waves, winter storms and ice storms together are 1%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Petersburg and similar climates
TownRatings has no climate map of the towns around Petersburg yet.
Climates most like Petersburg’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Petersburg, PA | 20° | 85° | 41" | 26" |
| Englewood, OH | 21° | 85° | 41" | 25" |
| Speedway, IN | 20° | 85° | 43" | 26" |
| Savoy, IL | 18° | 85° | 40" | 21" |
| Keokuk, IA | 18° | 86° | 40" | 23" |
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
Warmer than it used to be
The last 30 years in Petersburg averaged 1.0° warmer than the 1900s. The biggest change is in February (+2.1°).
A smaller shift than in 75% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Petersburg compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Petersburg’s place among Pennsylvania’s.
Petersburg weather by month
Highs, lows and precipitation from NOAA’s grid at Petersburg’s center; snow, wet days and snow on the ground from Williamsburg, PA. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 37° | 20° | 2.7" | 7.5" | 11 | 13 | 20° – 37° |
| February | 41° | 22° | 2.4" | 6.8" | 10 | 12 | 19° – 39° |
| March | 50° | 28° | 3.3" | 4.8" | 11 | 5 | 33° – 50° |
| April | 63° | 38° | 3.6" | 0.2" | 13 | 0 | 45° – 56° |
| May | 73° | 48° | 3.9" | 0.0" | 14 | 0 | 55° – 67° |
| June | 81° | 57° | 3.9" | 0.0" | 12 | 0 | 65° – 71° |
| July | 85° | 61° | 3.8" | 0.0" | 11 | 0 | 68° – 77° |
| August | 83° | 60° | 3.7" | 0.0" | 11 | 0 | 68° – 76° |
| September | 76° | 52° | 4.0" | 0.0" | 10 | 0 | 62° – 68° |
| October | 64° | 41° | 3.3" | 0.0" | 11 | 0 | 49° – 59° |
| November | 52° | 32° | 3.0" | 1.3" | 10 | 1 | 37° – 47° |
| December | 41° | 25° | 3.1" | 5.1" | 11 | 7 | 24° – 43° |
| Year | 62° | 40° | 40.9" | 25.7" | 136 | 37 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 19° to 39°. June is the most reliable, staying within 6°.
Where Petersburg’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Petersburg’s center.
- Snow: Williamsburg, PA.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Raystown Lake 2, PA, 13 miles from the town’s center, 290 ft higher; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Petersburg’s climate
What is the weather like in Petersburg?
A typical July afternoon reaches 85°, a January night drops to 20°, and about 26 inches of snow falls in a normal winter. Colder January nights than 57% of U.S. towns; cooler July afternoons than 50% of U.S. towns.
How cold does it get in Petersburg in winter?
January nights average 20°. About 126 nights a year reach 32° or below and 1 reach 0° or below. In the coldest January of the last 30 years the month averaged 20°.
How much snow does Petersburg get?
About 26 inches in a normal winter at Williamsburg, PA, heaviest from January through February, about 7 inches a month, with snow on the ground about 37 days a year.
How hot does it get in Petersburg?
July, with a typical high of 85° and a low of 61°. About 14 days a year reach 90° (Raystown Lake 2, PA).
When is the first and last frost in Petersburg?
In half of years the last spring frost (32°) comes by April 19 and the first fall frost by October 28, about 191 frost-free days, at Raystown Lake 2, PA.
What growing zone is Petersburg in?
Zone 6b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −1°.
What is the best time of year to visit Petersburg?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, August, September and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Petersburg getting warmer?
Yes: 1991–2020 averaged 1.0° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 75% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Petersburg.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.