Janesville, WI 53548 Weather

Key Messages

- Areas of fog look possible again tonight, mainly over east central and southeast Wisconsin. This fog may become dense in time for the morning commute.

- Marine Dense Fog in the nearshore waters early this morning.

- Dry with a gradual warming trend through next weekend.

Update

Issued 650 AM CDT Tue Oct 20 2026

Dense Fog Advisory remains in effect for northern and eastern portions of the CWA as overnight fog developed across parts of the area where conditions from cameras and observations were such that fog was becoming widespread and dense. As the sun comes up dense fog will gradually dissipate, most dissipating by 9am CDT but fully dissipating by 10am. It remains possible a 1 hour extension of the Dense Fog Advisory may be needed. Otherwise, high pressure remains in place and once fog clear conditions will be mostly clear and quiet the rest of the day. Some additional fog potential again tonight but appears likely to be less widespread and impactful than this morning.

Kuroski

Short Term

Issued 1118 PM CDT Mon Oct 19 2026

Current Overnight through Wednesday Night:

Short range guidance continues to hone in on the potential for fog overnight, mainly east of where a lake breeze pushed inland this past afternoon.

High clouds continue to exit and mostly clear skies will prevail overnight. This, in addition to subsidence overhead, light winds, and lake modified air at the surface, should allow for areas of fog to form east of said lake breeze boundary, mainly over the eastern half of the CWA. Guidance shows the potential for this fog to become dense in spots just in time for the morning commute. The fog may then linger until 9 or 10am given the lower sun angle and weaker mixing this time of the year. Visibility trends will be monitored for either an SPS or a Dense Fog Advisory during the early morning hours. Cautious travel is advised in any fog that develops.

After fog dissipates late this morning, expect mostly clear skies through the afternoon hours into the evening. Highs will be in the mid to upper 60s. With light east to southeast winds prevailing off of the lake, areas over east central WI will be a bit cooler.

A fog will again be possible tonight into Wednesday morning, mainly along the spine of the Kettle Moraine and east to the Lake Michigan shoreline owing to persistent weather conditions prevailing into Wednesday morning.

Long Term

Issued 1123 PM CDT Mon Oct 19 2026

Thursday through Monday:

A very quiet extended period is in store as high pressure will remain in place over the eastern half of the US and an upper level ridge builds over the Great Plains. The ridge to our west will result in high temperatures in the upper 60s to near 70 Wednesday through Sunday. There is some potential highs may even overshoot those marks, given yesterday already overshot guidance from the NBM.

The extended period will remain mostly dry, save for 10 to 15% chances for rain along a cold front over central WI Sunday night into Monday.

It does look like more fall-like temperatures will return following the cold front on Monday

CMiller