Average annual temperature is 12.9 °C
Absolute maximum temperature: 32.7 °C
Absolute minimum temperature: -16.3 °C
Number of sunny days: 173 days
Number of rainy days: 188 days
Number of snow days: 4 days
Look at detailed online map of West Islip
* Weather data for West 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) | 16.4 | 19.5 | 15.0 | 25.7 | 26.1 | 26.1 | 30.8 | 30.4 | 32.7 | 25.4 | 18.6 | 15.9 |
| Average daytime temperature (°C) | 8.3 | 7.7 | 9.4 | 15.6 | 19.1 | 22.9 | 27.9 | 26.3 | 23.8 | 18.9 | 11.2 | 9.3 |
| Average temperature (°C) | 5.1 | 3.7 | 5.3 | 11.5 | 14.7 | 18.9 | 24.3 | 22.7 | 19.9 | 14.8 | 7.1 | 5.8 |
| Average night temperature (°C) | 2.1 | 0.0 | 1.7 | 8.1 | 10.6 | 15.3 | 21.0 | 19.5 | 16.9 | 11.5 | 3.3 | 2.7 |
| Absolute minimum temperature (°C) | -2.0 | -16.3 | -2.9 | 1.1 | 5.2 | 9.8 | 16.8 | 16.1 | 11.9 | 7.5 | -3.9 | -3.9 |
| 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 | 6.8 | 7.4 | 8.6 | 12.3 | 11.6 | 11.8 | 10.7 | 8.1 | 8.1 | 7.4 | 5.6 |
| Precipitation (mm) | 128 | 51 | 148 | 146 | 63 | 103 | 144 | 173 | 226 | 96 | 48 | 212 |
| Sunny days | 10 | 16 | 16 | 13 | 21 | 10 | 8 | 15 | 13 | 14 | 19 | 18 |
| Rainy days | 20 | 10 | 14 | 17 | 10 | 20 | 23 | 16 | 17 | 17 | 11 | 13 |
| Snow days | 1 | 2 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
The best time to visit West Islip during the most sunny months:
The largest precipitation sum in West Islip is at