The official National Weather Service forecast for Monrovia — 39.5789°N, 86.4822°W, 2.4 miles from I-70. Forecasts here are written by NWS IND, this county’s forecast office.
| Morgan County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 36 | 41 | 52 | 64 | 74 | 82 | 85 | 84 | 79 | 66 | 53 | 41 | 63 |
| Avg low °F | 20 | 24 | 32 | 41 | 52 | 61 | 64 | 62 | 55 | 44 | 33 | 26 | 43 |
| Precip in | 3.2 | 2.7 | 3.8 | 4.6 | 4.9 | 5.2 | 4.4 | 3.0 | 3.2 | 3.4 | 3.1 | 3.2 | 44.7 |
1996–2025 normals for Morgan County — the climate division Monrovia sits in. All-time county record high 103.8°F (2012-07-08); record low -26.5°F (1994-01-19). Source: NOAA / National Weather Service.