Why adsense ravenue declining in June?

I see my cpc is declining in this month, no drop in traffic but the adsense CPC is low. Any insight on why this happen? is june the same as january usual drop?

Recently, Google AdSense changes many features. Some have been upgraded, some have been removed totally. And few will be changing soon. And those changes are causing the issue for the AdSense revenue drop.
What’s Changing?

Ad Sizes: Responsive Ads now default ads. Fixed size ads can be used as customization feature.

Ad Types: Text-only and display-only ad units are closed now. Both as mixed will be served and renamed it to “Display ads”.

Text Ad Styles: Ad styles for Text & display ads now off and only available for In-Feed and In-Article ads.

Simplifying “If No Ads Available”: This option has been closed. If there no ads, it will collapse or show black ads from now.

Is this the first time it happened?

How old is your site?

If this is the first time it happened and your site is less than a year old, you might be targeting a SEASONAL NICHE