The official National Weather Service forecast for Mullen — 42.0428°N, 101.0427°W, 62.4 miles from I-80.
| Hooker County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 37 | 40 | 51 | 60 | 69 | 81 | 87 | 85 | 78 | 63 | 50 | 39 | 62 |
| Avg low °F | 14 | 15 | 24 | 32 | 43 | 54 | 60 | 58 | 48 | 35 | 24 | 16 | 35 |
| Precip in | 0.4 | 0.6 | 1.0 | 2.4 | 3.9 | 3.8 | 3.2 | 2.2 | 1.8 | 1.6 | 0.6 | 0.5 | 22.0 |
1996–2025 normals for Hooker County — the climate division Mullen sits in. All-time county record high 107.8°F (1954-07-13); record low -29.8°F (1989-12-22). Source: NOAA / National Weather Service.