Another Phoenix weather thread: first 100 degree day of the year (2013, how much)

[Valley Native]

Summer doesn't officially start until June 21st, but I consider summer officially here when the temperature soars to 100 degrees or higher, and we did just that yesterday. It's interesting to note that over the last four years, the first 100 degree day of each year has been earlier than normal. On average, the first 100 occurs on May 13th ... however, this year we hit the mark ten days early (May 3rd). In 2011, 2012, and 2013, the first occurrence was in April.

This tells me that we are indeed getting hotter ... maybe not because of global warming, but because of the urban heat island effect. That usually affects overnight lows more noticeably, but I believe daytime highs have a tendency to be pushed upward because of warmer night/early morning temps. Anybody who is interested should check out the NWS Phoenix climatic page and observe how much warmer it has gotten over the course of time as we went from a small agricultural city long ago to a large sprawling metro area.

National Weather Service - NWS Phoenix

[Ponderosa]

According to NWS the average first day is May 2, so we were late this year. I think it used to be later, but more years in the books have shifted it earlier. I don't consider it "summer" until the spring weathers systems stop going through and it consistently is over 100. We have one such system coming in this week. Temps will be a good 10 degrees below normal with snow in the mountains. It ain't summer yet.

[Valley Native]

Originally Posted by Ponderosa

According to NWS the average first day is May 2, so we were late this year. I think it used to be later, but more years in the books have shifted it earlier. I don't consider it "summer" until the spring weathers systems stop going through and it consistently is over 100. We have one such system coming in this week. Temps will be a good 10 degrees below normal with snow in the mountains. It ain't summer yet.

Information concerning 100 degree and hotter temperatures for Phoenix, Arizona

According to the above weblink, the long term average for first 100 is May 13th. I'm sure that the average probably would be May 2nd if you include only the last 20 or 30 years ... and that would be all the more proof that we are getting hotter, and earlier. It seems like the only way to hold off on the 100s anymore until middle or late May is to have an El Niño weather pattern. That was the case during the last El Niño of 2010 when it didn't get to 100 degrees until May 21st. The strong El Niño of 1998 contributed to the first 100 degree temp not happening until June 2nd that year.

[Java Jolt]

Originally Posted by Ponderosa

According to NWS the average first day is May 2, so we were late this year. I think it used to be later, but more years in the books have shifted it earlier. I don't consider it "summer" until the spring weathers systems stop going through and it consistently is over 100. We have one such system coming in this week. Temps will be a good 10 degrees below normal with snow in the mountains. It ain't summer yet.

I didn't even know it reached 100 yet, it didn't feel too hot at all.

You're right that summertime is still a ways off, it won't be summer until the heat sticks around with no real break other than the occasional monsoon thundershower.

June, July, August, and part of September is the real summertime season here.

May is still a pretty decent month in spite of the brief spike in temperatures, it will turn cooler for a few days and warm up again.

[go09]

Originally Posted by Valley Native

Information concerning 100 degree and hotter temperatures for Phoenix, Arizona

...That was the case during the last El Niño of 2010 when it didn't get to 100 degrees until May 21st. The strong El Niño of 1998 contributed to the first 100 degree temp not happening until June 2nd that year.

I remember that year... May and June were so nice! It's what convinced me to stay here in AZ, lol.

[Thunder98]

Potential first 100 degree day next Wednesday? That is early this year!

[BIG CATS]

^

Bah humbug.

[maverick974]

With those temps, I'll be on the lake with the jet ski. Woohoo........

Summer is what you make of it............

[magnum0417]

I predict a 120 in june. Was 119 at the end of June of 13. The lack of precip since Jan going to further heat the concrete and asphalt of Sky Harbor .

[locolife]

Originally Posted by magnum0417

I predict a 120 in june. Was 119 at the end of June of 13. The lack of precip since Jan going to further heat the concrete and asphalt of Sky Harbor .

Please explain, this makes zero sense. Not the heat island effect but how rain now has anything to do with heat island effecting (during the day?? all things) the high temp in June?

This concept seems to by very misunderstood.