AydlettMany times, I am asked to speak to someone's belief, only to confirm a suspicion, a thought, a myth or otherwise.
I also hear frequently, that, “It's never been this hot before,” or it is simply getting hotter and hotter.
These statements can be flawed simply because it's what it feels like to someone at a given time, whether traveling from a wintertime location and returning to Guam or coming out of a wet and cloudy period of days or a week, back to the scorching, tropical sun. This is a common experience for most of us coming out of the December-February time frame when we experience our coolest and driest weather (and particularly the lower humidity).
Come April and May, we are burning up in Guam; the sun is high in the sky as we approach the summer months/summer solstice; the dry season is baking, and the rains usually have not returned yet, and won’t until around June and July.
Our warmest months of the year are April, May and June with the mean max temperature at 88.1, 88.6 and 88.7 F, respectively.
The coolest months (by mean maximum temperature) are December, January, February, March at 86.8, 85.9, 86.0, 86.9 Fahrenheit, respectively. By mean minimal temperature, those are January, February and March at 75.4, 75.0 and 75.6 F, respectively.
Our extreme daytime temperatures don't deviate so much, thanks to the surrounding ocean, but that's also true for our low temperatures.
We'll see daytime highs reach up to 91F and 92F. That's on the high end for us, but we typically keep around 88F to 90F for the warmer months and 86 to 87F for the cooler months.
Officially, we've reached as low as 69 degrees for nighttime low, but that was reached only a couple times in the last 20 years.
Unofficial sensors in some valleys have recorded low to mid 60s and I think one reached 59F some years ago, but that's rare and again, unofficial data.
Data and observations-wise, there have been changes to instrumentation, siting and methodology through the years. Climatologists seek to homogenize the data as best as they can.
Despite these issues, there is a clear signal of increasing temperatures.
Quantifiably, this is tricky to determine; but reliable evidence supports an overall gradual increase. Please see the charts.
Of note, global sea surface temperatures have been anomalously high the last couple years. This would impact the nighttime temperatures by limiting the degree of cooling overnight, and the 'feel' for ambient coolness in homes.
The number of 'cool' and 'cold' nights have decreased over the years (see the PIRCA report) while the number of warmer days has increased. mbj
Marcus Landon Aydlett is the warning coordination meteorologist for the National Weather Service’s Weather Forecast Office in Guam. He can be reached at marcus.aydlett@noaa.gov
