Autumn Continues but Summer Warmth Holds

Fall is that you? The autumnal equinox occured at 2:50 AM the Saturday morning of September 23 but summer has continued to stay beyond its welcome by more than 10 days and its not entirely a bad thing. A change in seasons at this time of the year brings rapidly falling temperatures, windy and cloudier / foggy days, and less daylight. Before we dive into that, let's recap some quick summer stats for 2023.

15 - # of days temp reached 90+ (first occurrence on June 2 and last occurence on September 5)
94 - hottest temp of 2023, which was reached on August 24
80 - dewpoint temp on August 25, 2023 was the highest since August 3, 2010
78 - the highest low temperature of 2023 occurred on August 24 and was the highest low since July 6, 2022. Additionally, it bested the previous record for the date of 77 set in 1936.
8 - the longest consecutive days with a trace or more of precipitation in the summer was recorded from June 29 to July 6
1.59" - the wettest day of the summer occurred on July 8 and helped contibuted to the 28th wettest July on record with a total of 6.06"
43% - the percentage of days that were both above and below normal for the months of June, July, and August totaling 86%, the remaining 14% (or 6 days) were at normal climatological levels. If you add in September and October (to date) the values come out to 64 days (or 51%) above normal, 54 days (or 43%) below normal, and 7 days (or 6%) at normal.
70 - highest wind gust speed (mph) of the year occurred on the afternoon of June 29 from a decaying derecho. Marked the highest gust speed since Apr 8, 2020
108 - the number of days (thru Oct 3) the temperature reached 80+ that first began on Apr 4 (average is around 100 days annually) - most is 131 days in 2007 & 2010
163 - the number of days (thru Oct 3) the temperature reached 70+ that first began on Feb 22 (average is around 160 days annually) - most is 186 in 2010
0 - the number of days the low temp dropped below 50 (beginning in June). This is the 4th consecutive year all 3 months (Jun-Aug) saw all of its days at 50+. This has also happened 7 out of the past 8 years. September also failed to drop below 50 which makes 2023 the 3rd year on record all 4 calendar months were 50+. The other 2 years were 2008 and 1925.


OCTOBER OPENS WITH LATE JULY and AUGUST-LIKE TEMPERATURES
The temperature on Sunday and Monday reached 84 and 85, respectively. These readings are the climatological averages for the first half of August. Additionally, the temperature on Tuesday reached a reading of 86° which is more typical for July. Another reading of 85+ is expected for Wednesday. These numbers are remarkably warm and there are only a few other handful of October days to reach this level of warmth or hotter. How many times has the temperature reached 85+ in October? We have had 96 out of a possible 4684 days since 1871 to reach temps ranging from 85 to 92, in the month of October. Only 6 of those days were 90+ with the last occurence happening on October 8, 2007. There was one year, the last 80+ degree reading occurred the following month on November 1, 1950. While we aren't exactly setting record temperatures, 2023 is in the top 2% for one of the warmest starts to Autumn.

Temperatures will begin a cooling process soon. Here's a look back at the last time we saw some cold numbers:

Last Occurrence	Low Temp	High Temp
below 70°	10/3/2023	6/12/2023
below 60°	10/1/2023	5/2/2023
below 50°	5/26/2023	5/1/2023
below 40°	5/3/2023	3/19/2023
below 30°	4/24/2023(NOTE)	3/18/2023
below 20°	3/19/2023	12/25/2022
below 10°	12/25/2022	12/23/2022
below 0°	12/23/2022	1/18/1994

NOTE: April 24, 2023 also marks the date of our last Spring Freeze


SUNSHINE AND WARMTH TO GIVE WAY TO SHOWERS AND COOLER TEMPERATURES
Wednesday will start off with temperatures in the lower to middle 60s across Indianapolis. Skies will generally be mostly clear so expect sunshine to greet us at sunrise, which now occurs a few minutes before 8:00 AM at this time of the year. Bright conditions and breezy winds should help boost temps back into the middle 80s for highs. We will see an increase of clouds that will mix down which may inhibit temps from reaching levels any higher than the 84°-87° range. Once the sun sets shortly after 7:00 PM, we may very well say goodbye to 80° warmth for the remainder of the year. Also of note, our streak of above normal warmth will reach 15 consecutive days with readings as much as 15 degrees above normal. Dry air will continue to hold during the overnight hours with temps likely only dropping into the mid 60s but the atmosphere may become more saturated on Thursday. A weakening cold front associated with a surface low passing to our North, could ignite a few light showers across the area anytime after sunrise Thursday. This will be the first of a few signals to a pattern change of dramatically cooler temperatures to wrap the week and enter the weekend. Scattered showers may continue Thursday afternoon and evening and ease up to only isolated or spotty chances for Friday and Saturday, where another cold front is poised to pass. Given breezy conditions, in tandem with cooler weather sliding in this may result in a WIND CHILL FACTOR! You may want to dress appropriately as it may feel cooler than it actually is, which is usually the case when the coldest air of the season ushers in. Some areas, likely away from city (urban heat island effect), will see frost on Sunday morning depending on how quickly winds subside. Frost forms when there is a break in clouds, light winds, and temps below 40. This criteria could also be met in some areas on Monday.

After the weekend, another dry streak emerges with more sunny weather that may help temps to quickly moderate to seasonal levels with lows in the mid to upper 40s and highs in the middle to upper 60s for much of the next week. A few 70s in some locales are possible but the transition in seasons will be hard to hold onto any meaningful prolonged periods of warmth. More cold jabs are likely in the weeks ahead.