Rainfall totals Islip, NY
For Islip, the official rainfall for the year to date is 30.72 inches through Aug 21, 2026, according to the National Weather Service daily climate report. The normal for that date is 29.02 inches.
Data from Islip Long Island MacArthur Airport, with records back to 1963.
Official rainfall report for Aug 21, 2026
| Measured | Normal | |
|---|---|---|
| Rain on Aug 21, 2026 | 0.41 inches | 0.14 inches |
| Month to date | 7.03 inches | 2.96 inches |
| Year to date | 30.72 inches | 29.02 inches |
| Record for Aug 21 | 1.31 inches | 1997 |
Source: National Weather Service daily climate report for ISLIP/MACARTHUR, issued the morning after Aug 21, 2026. The local National Weather Service office issues the daily climate report for the airport station the next morning, and that report is the official figure.
Days with measurable rain, 2026
| Date | Rainfall |
|---|---|
| Aug 17, 2026 | 0.66 inches |
| Aug 16, 2026 | 0.04 inches |
| Aug 13, 2026 | 0.08 inches |
| Aug 10, 2026 | 0.02 inches |
| Aug 7, 2026 | 0.58 inches |
| Aug 5, 2026 | 0.01 inches |
| Aug 3, 2026 | 1.95 inches |
| Aug 1, 2026 | 0.01 inches |
| Jul 30, 2026 | 0.19 inches |
| Jul 29, 2026 | 2.12 inches |
| Jul 21, 2026 | 0.03 inches |
| Jul 18, 2026 | 1.49 inches |
| Jul 9, 2026 | 0.01 inches |
| Jul 6, 2026 | 2.50 inches |
| Jul 5, 2026 | 0.09 inches |
| Jul 4, 2026 | 0.24 inches |
| Jul 1, 2026 | 0.94 inches |
| Jun 27, 2026 | 0.03 inches |
| Jun 26, 2026 | 0.13 inches |
| Jun 23, 2026 | 0.07 inches |
| Jun 22, 2026 | 0.12 inches |
| Jun 21, 2026 | 0.09 inches |
| Jun 15, 2026 | 0.20 inches |
| Jun 14, 2026 | 0.09 inches |
| Jun 12, 2026 | 0.01 inches |
| Jun 11, 2026 | 0.01 inches |
| Jun 8, 2026 | 0.01 inches |
| Jun 6, 2026 | 0.05 inches |
| Jun 1, 2026 | 0.01 inches |
| May 29, 2026 | 0.01 inches |
Through Aug 19, 2026, the GHCN-Daily station record shows 27.04 inches of measurable rain so far this year, falling over a 88-day span. Station observations are from GHCN-Daily, with a 1-3 day lag and quality checks by NOAA.
All-time rainfall records
| Wettest day | 13.51 inches | Aug 13, 2014 |
|---|---|---|
| Wettest year | 65.32 inches | 1989 |
| Driest year | 25.27 inches | 1965 |
| Average year | 45.02 inches | 62 complete years on record |
| Rain days a year | 116 | average, 0.01 inch or more |
| Record begins | 1963 | 22,983 daily readings |
Monthly rainfall normals
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Inches | 3.66 | 3.29 | 4.51 | 4.06 | 3.28 | 4.00 | 3.26 | 4.24 | 3.60 | 3.97 | 3.41 | 4.71 | 45.99 |
Averages are 1991-2020 normals from NCEI.
The daily climate report is issued by the local National Weather Service forecast office and delivered to this page by the Iowa Environmental Mesonet of Iowa State University. Under 17 U.S.C. 105, no copyright attaches to the government-produced figures on this page, including reports, alerts, station observations, and normals, which were created by the National Weather Service and other NOAA offices. The notice that 17 U.S.C. 403 requires appears in this sentence. It does not imply endorsement by or affiliation with those agencies. See: Data sources and attribution.