Average annual temperature is 12.8 °C
Absolute maximum temperature: 31.6 °C
Absolute minimum temperature: -16.0 °C
Number of sunny days: 174 days
Number of rainy days: 188 days
Number of snow days: 3 days
Look at detailed online map of Islip
* Weather data for Islip United States is based on climate observations for 2026 year
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Absolute maximum temperature (°C) | 14.9 | 18.3 | 13.8 | 22.4 | 24.0 | 24.8 | 29.5 | 28.6 | 31.6 | 23.9 | 18.0 | 15.5 |
| Average daytime temperature (°C) | 8.1 | 7.3 | 8.8 | 14.2 | 17.9 | 21.7 | 27.1 | 25.7 | 23.2 | 18.3 | 11.2 | 9.0 |
| Average temperature (°C) | 5.1 | 3.7 | 5.2 | 10.9 | 14.4 | 18.5 | 24.3 | 22.7 | 20.0 | 15.0 | 7.5 | 6.0 |
| Average night temperature (°C) | 2.2 | 0.1 | 1.8 | 7.9 | 10.7 | 15.6 | 21.5 | 19.9 | 17.3 | 12.0 | 4.1 | 3.2 |
| Absolute minimum temperature (°C) | -2.2 | -16.0 | -2.4 | -0.1 | 5.5 | 10.1 | 17.3 | 16.9 | 12.3 | 7.8 | -3.2 | -3.6 |
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight maximum duration (h) | 10.0 | 11.0 | 12.0 | 13.0 | 14.0 | 15.0 | 15.0 | 14.0 | 13.0 | 11.0 | 10.0 | 9.0 |
| Daylight mean duration (h) | 9.6 | 10.7 | 11.9 | 13.3 | 14.5 | 15.0 | 14.8 | 13.8 | 12.5 | 11.1 | 9.9 | 9.3 |
| Daylight minimum duration (h) | 9.0 | 10.0 | 11.0 | 12.0 | 13.0 | 14.0 | 14.0 | 13.0 | 11.0 | 10.0 | 9.0 | 9.0 |
| Sunshine mean duration (h) | 4.8 | 6.7 | 7.4 | 8.5 | 12.3 | 11.7 | 11.8 | 10.7 | 8.1 | 8.2 | 7.4 | 5.6 |
| Precipitation (mm) | 121 | 50 | 138 | 135 | 60 | 107 | 145 | 178 | 235 | 122 | 49 | 193 |
| Sunny days | 8 | 16 | 16 | 13 | 22 | 11 | 8 | 13 | 14 | 14 | 20 | 19 |
| Rainy days | 22 | 10 | 15 | 17 | 9 | 19 | 23 | 18 | 16 | 17 | 10 | 12 |
| Snow days | 1 | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
The best time to visit Islip during the most sunny months:
The largest precipitation sum in Islip is at