The official National Weather Service forecast for Williston — 44.4376°N, 73.0682°W, 3.2 miles from I-89.
| Chittenden County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 28 | 31 | 40 | 53 | 67 | 75 | 80 | 78 | 71 | 57 | 44 | 34 | 55 |
| Avg low °F | 10 | 12 | 21 | 32 | 44 | 54 | 59 | 57 | 50 | 39 | 29 | 18 | 35 |
| Precip in | 2.6 | 2.3 | 2.8 | 3.5 | 4.0 | 4.9 | 4.5 | 4.0 | 3.7 | 4.4 | 3.2 | 3.3 | 43.2 |
1996–2025 normals for Chittenden County — the climate division Williston sits in. All-time county record high 96.5°F (1975-08-03); record low -31.9°F (1994-01-27). Source: NOAA / National Weather Service.