The official National Weather Service forecast for Olathe — 38.8814°N, 94.8191°W, 1.4 miles from I-35.
| Johnson County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 39 | 45 | 56 | 66 | 75 | 85 | 89 | 87 | 80 | 68 | 55 | 44 | 66 |
| Avg low °F | 21 | 24 | 35 | 44 | 55 | 65 | 69 | 67 | 58 | 46 | 35 | 25 | 45 |
| Precip in | 1.2 | 1.4 | 2.6 | 3.7 | 5.5 | 5.2 | 4.1 | 4.3 | 3.5 | 3.4 | 2.1 | 1.5 | 38.5 |
1996–2025 normals for Johnson County — the climate division Olathe sits in. All-time county record high 110.0°F (1954-07-14); record low -20.6°F (1989-12-23). Source: NOAA / National Weather Service.