Highs in the 40s look likely. It's possible that Monday's high temperature could set a record as a the coldest high in Boston Marathon history. The current record is 48 degrees for the 2009 marathon. Any overnight showers will taper off before sunrise and before any of the start times. Runners can expect partly cloudy skies with a cool breeze.

Boston woke up under a stubborn marine layer this morning, with low clouds, patchy to dense fog, and temperatures stuck in the upper 40s. Visibility is poor in spots along the waterfront and through low-lying neighborhoods, so expect slower commutes. The afternoon high should top out near 49°F with a light northeast breeze around 5 to 10 mph.

What type of weather might runners expect for the 130th Boston Marathon on April 20? Here's an early look at the forecast.

Many people in Massachusetts will be getting their first real taste of summer this week. While temperatures have largely been above average since the beginning of March, there haven't been many real warm days. Boston has had just two days in the 70s thus far and inland locations (away from sea breezes) a few more.