Meteorological Fall
We have now put meteorological summer behind us and have now entered the fall season. The next few weeks there is still a chance of some warm days but after the 15th to the 20th there will be a noticeable decline in both daylight and temperatures.
Here are some averages for Grand Rapids for meteorological fall. The current 30-year average each of the fall months are September, Average mean temperature 63.5 Precipitation 3.43” snow fall 0. October average mean temperature 51.5 Precipitation 4.02” snow fall 0.3” November average mean temperature 40.0 precipitation 3.10” snow fall 7.1” The shorter 15-year average temperature for September is 64.2 precipitation 3.38” snow fall 0. For October the average temperature is 51.7 precipitation 5.04” and snow fall 0.2” For November the average temperature is 40.3 precipitation is 2.50” and snow fall 5.0” now looking back at the old 1981/2010 averages September old mean was 62.8 precipitation 4.28 snow fall 0. For October temperature 51.0 precipitation 3.26 snow fall 0.5 for November temperature 40.1 precipitation 3.51 and snow fall 6.8” over the last 40 years the temperature has moved upward, and precipitation has been more up and down. Snow fall has decreased a little.
The current 30-year average mean for meteorological fall at Grand Rapids is 51.6 the new 15 year average is 52.1. The record warmest autumn was in 1931 with a mean of 57.5° The coldest was in 1976 with a mean of 45.8. The wettest was in 1988 with 17.68” the driest was in 1956 with just 2.59” the most snow fall was in 2014 with 31.0” (all of which fell in November) the least snowfall was a trace in several years the last time was in 1984.
For the month of September as stated above the 30 year average mean is 63.5 the 15 year mean is 64.2. Since 1892 the warmest mean is 69.0 in 1931 the mean was 68.1 in 1933 and 1908, in 1921 the mean was 67.9 in 1906 it was 67.5 and in 2015 it was 67.2 for the top 5 warmest. The coldest mean in September is the 56.2 in 1918 with 56.4 in 1974, 56.5 in 1993, 56.9 in 1975 and the 58.1 in 1949 being the 5 coldest. Last year the mean was 65.6. In the last 5 years 4 of the 5 have been warmer than average. The hottest day in September was the 98 on September 2nd 1913. It reached 97 in 1954, 1953 and 1939 and 96 in 2017, 1960 and 1927 for the hottest days in September. Over the years it has reached 90 or better in 51 years so we can still get a hot day in September. The most days of 90 or better is 7 in 1931 there were 6 days in 2017. The last time it reached 90 or better in September was in 2018. The record low for the month is a cold 27 on September 28th 1991. It has gotten below 30 in September a total of 7 years and 32 or below in 24 years and below 35 (for a frost?) a total of 34 years. I have a picture on my phone of frost on September 19, 2020 when the official low of 36 was reported. The wettest September was in 1986 when a total of 11.85” of rain fell at Grand Rapids and the driest was in 1979 when just a trace was reported.
Slim
ADA – Well…this is an unexpected, very windy, heavy rain, Thunderstorm 😉 Sprinklers off.
6/10 of an inch in 30 minutes. Followed by…another 30 minutes of very low, very dark, dry clouds. Enjoyed the “atmosphere” though.
Thanks Slim. Good read as always. Do you know how many 80 degree days we’ve had this year? Seems we’ve had a lot, but maybe that’s because I’ve spent the whole Summer outside cleaning salvaged items from our fire.
At Grand Rapids so far there have been 77 days of 80 or better 1 in April, 9 in May, 17 in June 24 in both July and August and so far in September 2. The average number is 72 so Grand Rapids will end up above average. At Holland they reported 62 at Muskegon 75 and at hot Lansing they have had 86 so far. I have not verified the number at Holland. At Grand Rapids the most was in 2012 with 96 the least in 1924 with just 36. At Holland the most was a reported 109 in… Read more »
Wow the 109 80 degree days in 1895 is quite shocking
Definitely getting up there. I can see us reaching 90+ days this year the way it’s been going. Thanks!
Good thing 80’s isnt hot but Summer ish bring on snowstorms INDY
While you can not predict when the color will change, I came across this fall foliage prediction map where you can adjust the dates for an idea of when the leaves will be changing.
https://smokymountains.com/fall-foliage-map/
I think that that map has the change in Michigan too early.
Slim
The official H/L at Grand Rapids yesterday was 84/65, there was no rain fall and there was 62% of possible sunshine. The overnight low both here and at GRR was 64. For today the average H/L is 78/58 the record high of 95 was set in 1898 and again in 1953 the record low was a frosty 32 set in 1946. We have had many great days this warm season. One has to wonder if we will “pay” for this later in the year.
Slim