Wisconsin 7-Day Forecast: Highs Jump From 66°F to Mid-80s by Memorial Day Week

What changed

The National Weather Service forecast for south-central Wisconsin (MKX grid) shows a steady warm-up over the next seven days:

| Day | High (°F) | Overnight Low (°F) | |---|---|---| | Thursday night / Friday (May 22) | 66 | 44 (overnight before) | | Saturday (May 23) | 74 | 51 (Friday night) | | Sunday (May 24) | 78 | 52 (Saturday night) | | Memorial Day (May 25) | 85 | 54 (Sunday night) | | Tuesday (May 26) | 86 | 58 (Monday night) | | Wednesday (May 27) | 85 | 59 (Tuesday night) | | Thursday (May 28) | 82 | 59 (Wednesday night) |

Friday's high is forecast at 66°F with an overnight low of 44°F. By Memorial Day, the high reaches 85°F with a Sunday night low of 54°F. The warmest day in the outlook is Tuesday at 86°F, and overnight lows settle near 59°F by midweek.

Why it matters

For recently planted corn and soybeans, this kind of sustained warmth could speed up emergence and early vegetative growth. Daytime highs in the 80s paired with overnight lows in the upper 50s stack up growing degree days quickly. Fields that were planted into cooler soils earlier in May may see a noticeable push once this heat arrives.

The flip side: a fast warm-up can also increase moisture demand. If your area hasn't had recent rain, keep an eye on topsoil moisture — especially on lighter soils where young seedlings are just getting established.

What to watch next

• Updated NWS forecasts later this week for any shifts in the timing or intensity of this warm-up.
• Soil moisture conditions heading into the heat — the combination of warmth and adequate moisture is what drives strong early-season growth.
• USDA Crop Progress (released Monday evenings) for Wisconsin planting and emergence numbers.

Source notes

All temperature data from the U.S. National Weather Service API, MKX grid point (south-central Wisconsin): NWS Forecast. Forecast retrieved May 25, 2026.