The official National Weather Service forecast for Marathon — 24.7138°N, 81.0904°W, population 9,733, 90.3 miles from I-95. Forecasts here are written by NWS MFL, this county’s forecast office.
| Monroe County | J | F | M | A | M | J | J | A | S | O | N | D | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 77 | 80 | 82 | 85 | 89 | 91 | 92 | 92 | 91 | 87 | 82 | 79 | 86 |
| Avg low °F | 58 | 61 | 62 | 66 | 70 | 75 | 76 | 77 | 76 | 72 | 66 | 62 | 68 |
| Precip in | 1.5 | 1.8 | 1.9 | 2.5 | 4.4 | 8.0 | 6.6 | 7.4 | 7.9 | 4.5 | 2.3 | 1.8 | 50.6 |
1996–2025 normals for Monroe County — the climate division Marathon sits in. All-time county record high 97.1°F (1998-07-04); record low 30.5°F (1977-01-20). Source: NOAA / National Weather Service.