The official National Weather Service forecast for Le Mars — 42.7942°N, 96.1656°W, population 10,138, 24.1 miles from I-29.
| Plymouth County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 28 | 33 | 46 | 60 | 72 | 82 | 85 | 82 | 77 | 63 | 47 | 32 | 59 |
| Avg low °F | 10 | 13 | 25 | 36 | 48 | 59 | 63 | 60 | 52 | 39 | 26 | 15 | 37 |
| Precip in | 0.7 | 0.8 | 1.6 | 2.9 | 4.2 | 4.6 | 3.5 | 3.6 | 2.8 | 2.4 | 1.2 | 1.1 | 29.4 |
1996–2025 normals for Plymouth County — the climate division Le Mars sits in. All-time county record high 104.4°F (1988-06-22); record low -28.1°F (1970-01-19). Source: NOAA / National Weather Service.