The official National Weather Service forecast for Hillsborough — 43.1141°N, 71.8992°W, 11.3 miles from I-89.
| Hillsborough County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 32 | 36 | 44 | 57 | 68 | 77 | 82 | 80 | 73 | 60 | 48 | 38 | 58 |
| Avg low °F | 15 | 16 | 24 | 34 | 45 | 54 | 60 | 58 | 50 | 39 | 29 | 21 | 37 |
| Precip in | 3.4 | 3.2 | 3.9 | 4.2 | 4.0 | 4.4 | 4.2 | 3.8 | 4.0 | 5.0 | 3.5 | 4.4 | 48.0 |
1996–2025 normals for Hillsborough County — the climate division Hillsborough sits in. All-time county record high 98.2°F (2025-06-25); record low -26.6°F (1957-01-14). Source: NOAA / National Weather Service.