Mean annual temperatures refer to the average of the maximum and minimum temperatures of a year, taking the mean average of the coldest month of the year and averaging it with the mean average of the hottest month of the year. The mean annual temperature is a valuable climatology tool that can assess an area’s climate change.
To calculate the mean daily temperatures of an area, usually a town or city, for each day of the year: Take the temperature readings on the hour for a 24-hour period. Add the hourly readings together, then divide that number by 24 to get the mean daily temperature. Record the first measurement at midnight and the last at 11 p.m. of the same day.
Calculate the mean monthly temperature by adding up the daily mean temperatures for each day of a month and then dividing that sum by the number of days in the month. For example, for the month of January, add up the 31 mean daily temperatures, then divide by 31. For the month of February, add the 28 mean daily temperatures together, then divide by 28 (in leap years, add the 29 mean daily temperatures and divide by 29).
There are other methods which are used to calculate temps for an area which are median and quartile, however we won’t get into that here as mean temps seem to be the most used by climatologists.
This is the rainfall which fell in the Wednesday night Thursday morning time frame – we didn’t get any here in the Otsego Plainwell area – we have had .69 of an inch this month and the last decent rain we had was on August 8th.
We currently have a dense fog advisory for the counties inland from the lake which is set to expire at 10am. Today will be another pleasant day with highs in the mid to upper 70s with chances of rain and storms after 5pm. As of now the heat and humidity will set up camp over the state for the weekend into early next week. Below is the NWS prediction for rain this evening.
For the daily average, are the high temp and low temp not factored in at all then if they don’t happen on the top of the hour? For example if the 2 p.m. temp is 85, but at 2:15 it hits 89 but then drops back to 85 at 3 p.m., is the 89 never used in the equation then?
Barry, If the temperature was 85 at the 2 PM reading but reached 89 between 2 PM and 3 PM and that was the high for that day, Then the high for the day would be 89. As for the average for a given day (I will use yesterday at GRR) the high was 73 and the low was 60.If you add the two together you get 133 and divide by 2 you get 66.5° and that was yesterdays average mean temperature at GR. Note if you look up the hourly reports for yesterday there were no hourly reports of… Read more »
I meant for the daily mean where you add up the 24 Remus from the top of the hour and divide by 24.
You know that is one way that it can be done but you could get two different readings depending on what one you use. I will drop a line to the NWS to see if they will shed some light as to what one they use and how they determine what one to use if their is a difference of more then a tenth of a degree.
Slim
BTW I know the NWS rounds up and or down by a tenth of a degree and as far as I can tell you will get a days mean average as reported in the monthly mean averages by add the H/L and dividing by 2. But in truth I do not know what method they NWS uses the same difference you mentioned can happen on lows as well so you could have a day that got warmer during the day between hours and and a low that did the same thing all in one day. I am sure they have… Read more »
I’ve always wondered which method was used. Most days they prob come out close to the same, but there are days when it could be a decent difference with big temp swings, like during a quick thunderstorm.
I sent off a letter to the NWS and will let you know if I get a reply back
Slim
I suppose if one were ambitious they could record the temperature for every minute of the day and divide it by 1440 to get an average 🙂
Good point. lOL
Slim
I’m kind of surprised they don’t have a computer to keep track of it. Would not take much at all to set up a program to record data every minute. It would be highly accurate!
We are now at the half way mark (well almost) of August 2019 and here at Grand Rapids the mean temperature so far this month is at 72.6 that is good for a departure of +0.9° the warmest so far has been 89 and the lowest so far has been 55. This has been a sunny month so far with just 2 cloudy days and 13 clear or partly cloudy days. So far at the airport there has been 1.01” of rain fall and that is a departure of -0.74”
Slim
Yesterdays high of 73 at Grand Rapids was the coolest high since June 20th and it also broke the string of days where the high at Grand Rapids was 78 or better (that 78 has no meaning it was just a number I picked as it was the coolest reading for a high in July 2019) so 2019 will be in a two way tie for the most days (55) in a row where the high in GR was 78 or better. BTW the years with the most total days of 1. 80 or better is 2012 with 96 (so… Read more »
Quite a long stretch without any cool cloudy days. In our area there was almost no rain during that stretch, probably why there was never a cool down day. Yesterday mornings rain was 3 times more than we’ve had total during that whole stretch.
yes, that was a long stretch of very warm days. And many times the humidly was also very high. I found a site that records the highest and lowest DP for a day but it don’t keep records for the past dates so one would have to do that them selves and keep the record. I might make up a spread sheet and see how that goes but if I started now it still would be a short record.
Slim
It’s going to be a warm and steamy several days!
Starting the day out at -8 degrees below average low out at thee YARDofBRICKS NE of GR 53* cool degrees no air conditioning no fans and our windows wide open with a blanket on love it have a super Friday the weekend is here …INDY ..