September 2015 could be the warmest on record

The dry and very warm weather continued for one more day with temperatures reaching well into the 80s earlier. This September continues to on the extreme side of warm. While you might be enjoying the long summer, if we were in this pattern during June or July, we’d be sizzling in the upper 90s to century mark.


The shorter days and lower angle of the sun is preventing the ground and subsequently the air, from getting even warmer than it is in this pattern. It’s not unusual to have some 80 degree days right through September, but they are usually peppered between cooler ones. Typically, the last 80 degree occurs about September 29th. On the other end of the warm season, the average date of the first 80 degree day is on May 1st. These are based on 30 year averages

Earlier Warmth
What’s really quite interesting is if you look at the average dates of the first and last 80 degree day in Boston over the past 15 years. In that short time span the first 80 degree day occurs on average about a week earlier than it had been. Since the turn of the century, 9 of the 16 years have seen the first 80 degree day occur in April.
Digging a bit deeper, the final date of an 80 degree occurrence is October 1st, during the past 15 years that day has moved only by one day later.

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Warmest September On Record Is Possible
Getting back to our current warm spell, presently September’s average 5 degrees above the 30 year mean. We are on pace to have the warmest September on record, but during the final 10 days the temperatures will be close to average or even a bit below. While it’s likely we end up near or at the top of warm Septembers, it won’t be as extreme as it is today.

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Lack Of Rain
Depending on your lifestyle the lack of rain might not even be a factor. If you live in a condo or apartment with little outdoor space, the only indication we need rain might be you are watering your containers more often. However, if you have any size lawn, flower bed or vegetable garden you clearly have noticed it’s very dry. The shadows this time of year are longer, therefore the sun isn’t beating down on many areas as much and this helps plants make it through dry spells. However, if you have –over-seeded your lawn, or put in new trees and shrubs, it’s important you water them well until we do see significant widespread rain.

The weather maps in motion over the next two days show how high pressure (H) will move out to see as a cold front (blue line) moves through the area. Behind the front another area of high pressure (H) takes control of the weather for much of next week.

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The second area of high pressure has Canadian air associated with it and therefore it is much cooler than the air we have been experiencing this month. It’s not going to be so chilly you’ll need the heat or anything like that, but it will feel more like the weather you’d expect for the autumnal equinox next week.

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