This Summer Was Record Breaking

Its September 1st, which means its officially the start of Meteorological Fall and the end of Summer. This summer was definitely one for the record books. Looking back, the span from June 1 - August 31 ended up seeing the most 100 degree days on record (27). I'm still questioning the validity that the airport hit or exceeded the 100 degree mark 27 times, but the SLC NWS issued a graphic today, basically certifying that it is correct. 

In addition to us shattering the record for most 100 degree days this summer, we also set the record for hottest average temperatures over the 3-month span. The average temp for the entire June/July/August period came out to 81.5 degrees. That's 0.6 degrees warmer than 2021 and 2017 which similar hot and had average summer temps of 80.9 degrees. 

Sadly, it won't feel like fall anytime soon as the record heat only looks to continue. A very strong ridge of high pressure for early September looks to remain over the Southwest US for the nest 5 days and keep the threat for 100 degree days going in Salt Lake. Today's forecast high of 101 would break the all time record high for September and the additional 100 degree days in the forecast would pile up as the most 100 degree days ever observed in September. Sooner or later the pattern will break and we will get a nice cool front to come through, but until then, try not to fry up. 

Temperature Sensor at KSLC Correct?

Yesterday the temperature at Salt Lake City Intl. Airport reached or exceeded the 100 degree mark for the 22nd time this summer (June 1-Present). That breaks the all-time record for most 100+ degree days in a year for Salt Lake City, UT. Nearly all valley stations reporting to MesoWest yesterday afternoon were running below 100 degrees at the time the airport reached the 22nd 100 degree mark. This made me wonder. Is the temperature sensor reporting correctly? Have we really reached 100 degrees 22 times in Salt Lake this year

We know that the SLC airport ASOS is located at the lowest point of the SL Valley (4226 feet). It sits in a field that has no vegetation and is at the south end of the airport's runways 17/35 and  14/32. The no vegetation and nearby black topped runways could possibly explain why the temperature sensor at the ASOS typically runs about 2-5 degrees warmer than anywhere else in the valley. However, there is another weather station in close proximately that tells a different story. 

                                    KSLC and UDOT's Weather Station Valid: 8/17/2022 at 11:00 MDT

                                            Distance between KSLC and UDOT I-215@I-80

The weather station is located approximately 0.83 miles to the southeast of KSLC. It sits on the shoulder of two highways, in between the interchange of I-215 and I-80. The weather station is owned by the Utah Department of Transportation. I know this because I used to work for the company that maintains all of UDOT's weather stations and know for certain that the temperature sensor  at that particular site  is highly accurate and is properly position/calibrated. When comparing KSLC temperature data over the summer months to that of UDOT's station I-215 at I-80, I noticed some big differences.

KSLC's temperature reached or exceeded 100 degrees 22 times, while UDOT's weather station at I-215 and I-80 only reached or exceeded 100 degrees 5 times. Now UDOT's weather station sits at the same elevation as KSLC and is located right off the side of the highway in a field with no vegetation around. One would think the temperatures would be identical, but they are not. 

Daily high temps observed at KSLC and days where the high temp reached or exceeded 100 F.

Daily high temps observed I-215/I-80 and days where the high temp reached or exceeded 100 F.

Now the ASOS temperature sensor may be different from the one used by UDOT's nearby weather station, but the observed temperatures at both locations should not be that drastically different. It makes me wonder if the temperature sensor at KSLC is calibrated properly and if not, how valid is the claim, "SLC broke the all-time record by hitting or exceeding 100F 22 times this summer". 

 Hottest July on Record In SLC

If it feels like July 2022 has been hot, that's because it has. In fact, July 2022 is on pace to be the hottest ever, since observations for Salt Lake City were first recorded back in 1874. 

What's even more remarkable about this long term graph, is the rise in July average temperatures just within the last 32 years. If we zoom in, we can see that the overall average temperature for the July 1 - July 19 period has risen 8 degrees, from around 76 degrees in 1990 up to 84 degrees so far this year. What's even worse is that the 3 hottest July 1-19 periods on record all happened within the last 5 years.  

After looking at forecast models for weather conditions through the end of the month, I'll take my bets that this month ends up being the hottest ever. 

 Windy Spring In Utah

I noticed a lot of people on social media were complaining about the weather, more so about how windy it had been here in Utah this Spring. It did seem unusually windy in the beehive state during the Spring months, especially during the months of May and June. This sparked my interest so I decided to do some digging to see what I could find out.

Finding archived wind data turned out to be pretty difficult. The National Weather Service office here in Salt Lake City does not keep any daily wind data records. After searching the web however, I was able to find some archived wind records for Salt Lake City from NOAA's National Centers For Environmental Information webpage https://www.ncdc.noaa.gov/cdo-web/search. One data set in particular had daily wind observations for Salt Lake City that stretched all the way back to the year 1997. This data set consists of the fastest daily wind speed that was observed at the SLC Airport. I was hoping to find the fastest daily wind gusts observed but fastest daily sustained wind speed worked out just fine.

 First, I broke the data set up into years, then I separated it by months. Because May and June seemed unusually windy for this year, I broke the data up into those two months, then I averaged out the daily fastest wind speeds over those two month periods for each year. In the end I found some interesting results.

May and June of 2022 turned out to be the windiest May/June period in SLC in the last 17 years. The next closet comparable years are 2020 and 2005. Its important to note that the wind data used to make this graph includes wind speeds from all directions.

Given that it was also windy in the southern portions of Utah, I decided to see if I could find some wind data for the St. George area. Unfortunately, the same data set for a reliable point in the St. George area was only available for the past 3 years. Cedar City airport had records going all the way back to 1998 so I decided to use that to represent southern Utah. The result for Cedar City was dramatically different, in that 2021 had a windier May/June period. In fact, the past 3-years combined have been the windiest on record dating back to 1998.

Overall, I guess its safe to say that May/June were usually windy in here Utah, and if you live in southern Utah, the past 3 May/June periods were very windy.