The official National Weather Service forecast for Mendenhall — 31.9618°N, 89.8701°W, 21.8 miles from I-20. Forecasts here are written by NWS JAN, this county’s forecast office.
| Simpson County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 59 | 64 | 71 | 77 | 84 | 90 | 92 | 92 | 88 | 79 | 69 | 61 | 77 |
| Avg low °F | 36 | 40 | 46 | 53 | 61 | 68 | 71 | 70 | 65 | 53 | 43 | 39 | 54 |
| Precip in | 5.7 | 5.5 | 6.0 | 5.6 | 4.2 | 4.7 | 5.2 | 5.0 | 3.7 | 3.2 | 4.1 | 5.3 | 58.2 |
1996–2025 normals for Simpson County — the climate division Mendenhall sits in. All-time county record high 105.4°F (2000-08-31); record low 0.7°F (1962-01-12). Source: NOAA / National Weather Service.