Apart from some smoke from wildfires drifting into the region from Idaho and eastern Oregon, our skies should remain mostly clear thanks to a ridge of high pressure that will stay put. Temperatures will remain well into the 90s through the weekend, with a few afternoon clouds popping up Sunday that could turn into thunderstorms, especially on Monday. For the rest of the week, sunny weather returns with temperatures staying into the low 90s.

Seasonal lag

On another topic, Kemp Shiffer had the following: “I have a question about ‘summer heat’. Why is it that July and August are much warmer than May and June, when the sun reaches its maximum on June 21? It seems to me that the 6 weeks prior to and just after June 21 should be the warmest but that is never the case?”

Equinox

This is a very common misconception about the seasons and temperatures. Logic would dictate that the temperature should be the warmest when the sun is the highest and the days are the longest. But there is a 4-6 week lag in the maximum heating in the northern hemisphere due to an energy imbalance. Think of it this way. On any given 24 hour day, any location on the earth gains heat during the day, and then loses it during the night. If it gains more heat during the day than it loses at night, then there is a net heat gain, and the average temperature will increase every day that there is that energy imbalance. On the solstice the northern hemisphere is maximizing its heat gained vs heat lost, so the day after the average temperature is still higher. There is still a daily net heat gain for about a month or so afterward, until late July-early August, after which the earth starts to lose more heat at night than it gains during the day, and the average temperature starts to cool.

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