The official National Weather Service forecast for Hyannis — 41.6529°N, 70.2828°W, 24.6 miles from I-495.
| Barnstable County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 39 | 41 | 46 | 55 | 64 | 73 | 79 | 79 | 73 | 63 | 53 | 45 | 59 |
| Avg low °F | 25 | 26 | 31 | 39 | 48 | 57 | 64 | 63 | 57 | 47 | 38 | 30 | 44 |
| Precip in | 4.3 | 3.6 | 4.6 | 4.3 | 3.6 | 3.5 | 2.7 | 3.5 | 4.3 | 5.0 | 3.9 | 4.6 | 47.9 |
1996–2025 normals for Barnstable County — the climate division Hyannis sits in. All-time county record high 95.8°F (1991-07-22); record low -9.4°F (2023-02-04). Source: NOAA / National Weather Service.