Today's weather map looks more like mid-July than mid-October. The big surface high pressure system off the southeast coast will blanket the eastern third of the country with unseasonably warm weather over the next few days. The city is expected to warm to the upper 70s this afternoon and close to the record highs of 82 tomorrow and 83 on Wednesday.

How unusual is that warming? By definition breaking a record means the warming is unprecedented, but let's look at the climatology a bit deeper to see how unusual it is.


Plotting out the probability that the high will exceed 80 degrees, or the low falls below 32, shows a couple of interesting trends happen around this time of year. Based on the last 50 years of Central Park's daily data, this week is when the chance of hitting 80 pretty much falls to zero.

Except for one crazy day in November 1993, the last time we had an 80-degree day this late in the season was in 1979. This week is also when freezing temperatures first become possible in the city, though the average first day below freezing is closer to the beginning of December.

Cooler weather, but nothing near frost, will arrive once a cold front passes on Wednesday night. Thursday will still warm to at least the lower 70s but we could see highs only in the mid 50s by Sunday. The next chance of rain looks to be on Friday, depending on what happens with a weak tropical disturbance that is currently east of the Bahamas.