Philadelphia's airport got 21.08 inches of rain from July to September 2026, the third most since 1940

Tue, 06 Oct 2026 08:39:29 -0400

Philadelphia International Airport recorded 21.08 inches of rain from July 1 through September 30, 2026. That is the third-highest total for those three months in the station’s record, which starts in July 1940, behind 32.29 inches in 2011 and 22.41 inches in 2013. It is 8.01 inches above the 13.07 inches the airport averaged for the same months from 1991 through 2020. The figures are this site’s totals from NOAA’s daily records, as served by the Applied Climate Information System (ACIS), and the station is missing no days in the period.

July to September 2026 was the third wettest at the airport since 1940

Precipitation from July 1 through September 30 each year, Philadelphia International Airport, 1940 to 2026

Totals summed by Conshy Roofers from NOAA monthly precipitation. July to September 2026 readings are preliminary. Source: data.rcc-acis.org

Month by month

July brought 7.03 inches, August 7.44 and September 6.61. None of the three ranked among the five wettest of its own month at the airport. Each came in more than 2 inches above its 1991 to 2020 average, and 2026 is the only year in the record when all three months reached 6 inches.

Precipitation at Philadelphia International Airport and Norristown, July to September 2026, with the airport's 1991 to 2020 average for each month. Norristown's days end at its 7 a.m. reading.
Month	Airport 2026 (inches)	Airport 1991 to 2020 average (inches)	Airport days with 1 inch or more	Airport wettest day (inches)	Norristown 2026 (inches)
July	7.03	4.38	2	2.70	4.21
August	7.44	4.29	3	2.33	8.59
September	6.61	4.40	3	1.58	6.97
July to September	21.08	13.07	8		19.77

Source: data.rcc-acis.org

The airport had 8 days with an inch or more of rain, against an average of 3.87 for the same months from 1991 through 2020. That ties 1967 for the third most in the record, after 10 in 2011 and 9 in 2013. Two of those days brought more than 2 inches: 2.70 inches on July 9 and 2.33 inches on August 27. Measurable rain, a hundredth of an inch or more, fell on 32 of the 92 days.

Four of the 87 years on record topped 20 inches from July through September: 1971, 2011, 2013 and 2026. The years 2010 through 2019 averaged 15.02 inches for the three months, against 11.26 inches from 1941 through 1970.

Closer to Conshohocken

NOAA’s Cooperative Network station in Norristown, USC00366370, sits just up the Schuylkill from Conshohocken. Its precipitation record in ACIS starts in May 1948 and has gaps. It recorded 19.77 inches from July through September 2026 with no days missing, the sixth most among the 54 years since 1948 when the station has every day of those three months.

The two stations split the summer differently. Norristown had 4.21 inches in July, well under the airport’s 7.03, and 8.59 inches in August, more than the airport’s 7.44. Norristown counted 9 days with an inch or more, the third most among its complete years after 10 in 2011 and 10 in 2018. ACIS lists the Norristown readings as taken at 7 a.m., so each of its days covers the 24 hours ending that morning. A storm on a summer evening lands on the next day’s line, which is why the two stations’ heavy-rain dates often differ by one.

What this means for a roof

The National Roofing Contractors Association recommends inspecting a roof at least twice a year, in spring and fall, and says to pay special attention to valleys, gutters and roof drains, where debris collects and slows drainage. A valley is the channel where two roof slopes meet. This fall’s inspection is the first chance to check those spots after the wet summer.

Indoors, a stain on a top-floor ceiling or on the attic side of the roof deck after one of the heavy days is worth a closer look from the attic or by a roofer. The roof inspection checklist lists what to check.

If water came in, the Pennsylvania Insurance Department’s natural disaster guide tells homeowners to photograph or film the damage before cleaning up, to make only the repairs needed to prevent more damage, and to hold off on permanent repairs until the insurer approves them. The same guide suggests asking the insurer whether damage from floods and wind is covered under the policy, since that decides what a claim can include. Whether a given leak is covered depends on the policy wording, so ask the insurer or an agent. The storm damage and insurance claims guide covers the claim process and its deadlines.

Caveats

The National Weather Service says daily observations are preliminary until NOAA’s National Centers for Environmental Information finishes quality control, three or more months after they are taken. The July to September 2026 figures can still change.

Norristown’s July total, 2.82 inches below the airport’s, shows how far two stations in the same region can differ in one month. Neither station measures rain on a particular street in Conshohocken or West Conshohocken.

The 1991 to 2020 averages here are this site’s averages of the airport’s own monthly totals, not NOAA’s published climate normals. Norristown’s comparison uses only the years when it reported every day from July through September, which leaves out many years and makes its ranking less certain than the airport’s. The weather guide covers the area’s rain over the full year, along with freeze-thaw days, wind and hail.

Rain | Conshy Roofers

Philadelphia's airport got 21.08 inches of rain from July to September 2026, the third most since 1940

Month by month

Closer to Conshohocken

What this means for a roof

Caveats