The official National Weather Service forecast for Philadelphia — 35.6795°N, 84.4038°W, 2.9 miles from I-75.
| Loudon County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 48 | 53 | 62 | 71 | 79 | 86 | 88 | 88 | 83 | 72 | 61 | 52 | 70 |
| Avg low °F | 29 | 33 | 39 | 46 | 56 | 64 | 68 | 66 | 60 | 48 | 38 | 33 | 48 |
| Precip in | 5.0 | 5.2 | 5.0 | 4.8 | 4.3 | 4.4 | 4.9 | 3.8 | 4.3 | 3.3 | 4.2 | 5.6 | 54.8 |
1996–2025 normals for Loudon County — the climate division Philadelphia sits in. All-time county record high 104.6°F (2012-07-01); record low -13.3°F (1985-01-21). Source: NOAA / National Weather Service.