Irmo, Columbia Weather
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Climate of Irmo: monthly averages
Based on 25 years of satellite and reanalysis data (2001-2025), July is usually the hottest month in Irmo, with average daytime highs around 33°C. January is the coolest, when nights typically fall to about 1°C and frost is possible on the coldest nights. That is a wide yearly range of roughly 33°C, so the seasons feel very different from each other.
The area receives about 1150 mm of rain in a typical year. Most of it falls from June to August and December, and June is the wettest month at roughly 119 mm.
For outdoor plans and travel, March to May and September to November usually offer the most comfortable weather in Irmo, with mild days and relatively little rain.
| Month | Avg high | Avg low | Rainfall | Humidity |
|---|---|---|---|---|
| Jan | 12° | 1° | 77 mm | 80% |
| Feb | 14° | 3° | 90 mm | 80% |
| Mar | 18° | 6° | 94 mm | 79% |
| Apr | 23° | 11° | 78 mm | 75% |
| May | 28° | 16° | 94 mm | 71% |
| Jun | 32° | 21° | 119 mm | 70% |
| Jul | 33° | 23° | 119 mm | 69% |
| Aug | 33° | 22° | 117 mm | 71% |
| Sep | 30° | 19° | 97 mm | 71% |
| Oct | 24° | 12° | 81 mm | 72% |
| Nov | 18° | 6° | 77 mm | 73% |
| Dec | 14° | 3° | 109 mm | 80% |
Source: NASA POWER (MERRA-2 reanalysis), averaged over the roughly 50 km grid area around Irmo. Values describe typical conditions, not a forecast.
About Irmo weather
Irmo is a place in South Carolina's humid subtropical climate, coastal and low-lying for much of the state, located about 157 km south-east of Greenville. Irmo gets hot, humid summers (June–August) with highs commonly in the low-to-mid 30s°C each year. Irmo closes out the year with mild winters (December–February), rarely dropping below freezing near the coast. This page shows live, auto-refreshing weather for Irmo: current conditions, an hourly breakdown, a 16-day outlook, a date-lookup tool for any past or future date, and real-time air quality, sourced from Open-Meteo. Local timezone: America/New_York.
Frequently asked questions
Irmo is about 157 km south-east of Greenville, in South Carolina.
Irmo sees mild winters (December–February), rarely dropping below freezing near the coast.
The live current conditions, hourly forecast and 16-day outlook above are pulled in real time for Irmo's exact coordinates. No fixed schedule, the page updates whenever you load it.
July is usually the hottest month in Irmo, with average daytime highs of about 33°C and nights around 23°C.
The coldest nights come in January, when the average low is about 1°C and daytime highs reach around 12°C. Frost is possible on clear, calm nights.
Irmo receives about 1150 mm of rain in a typical year. June is the wettest month at roughly 119 mm, and the main rainy period is June to August and December.
March to May and September to November usually offer the most comfortable weather in Irmo, with mild daytime temperatures and little rain.
In November Irmo typically sees daytime highs near 18°C and lows near 6°C, with about 77 mm of rain over the month and average humidity around 73%. Check the live forecast above for this week's actual conditions.
Up to 16 days ahead using the extended forecast and date picker above; further-out or historical dates use the same date lookup tool.
The current temperature for Irmo updates automatically at the top of this page — scroll to the hourly strip below to see how it's expected to change over the day.
Irmo's day-to-day weather follows the broader pattern of South Carolina described above. See the hourly weather forecast or the air quality index for more detail.