Here's an updated version!
View attachment 891525
As the data usually says about Marathon Weekend,
prepare for everything. The above table shows that you have a near equal chance of all five different levels of T+D during the typical dates of MW. A near 20% chance of Ideal, Good, OK, Not great, and Bad. And even within a weekend can have an Ideal on the 5k, and by the time the marathon rolls around you've moved straight to Bad. The one trend that exists is that despite only covering a 6 day period on the calendar, you are more likely to have better temps on Jan 6th than Jan 12th. The 2025 marathon weekend is late (Jan 8th-12th). So it's a higher chance of warmer temps than ideal temps. The Jan 12th date has had a split of 15% occurrence of ideal/good, 31% occurrence of ok, and 54% occurrence of not great/bad.
For reference, the
@runwithperseverence7 was inquiring about a T+D of 148 at the start (74 temp and 74 dp). In the 51 date/year combos above, that has not occurred. But the T+D had gone above 148 by 11:30am once on Jan 12th, 2020. The Jan 12th, 2020 race peaked at 84 temp with 69 dp (T+D 153) at 1:53pm according to weather underground.