Fertilizing perennials

We are currently having incredibly warm, humid weather. Today's temp was 98. It may be cooler tomorrow. Question--should I wait for it to cool down to spray my perennials with a fertilizer, or does it matter?

Thanks!

the temperature today in my garden was 80F. I water and fertilise my plants as soon as the sun is about an hour from sunset. this gives them all night and a few extra hours to make use of the water I give them.

have you tried granular rose fertiliser around your plants? I use it to put around all my perennials.

Mark

Thanks for replying. I have rose fertilizer, and I may give that a try. I hate to spray chemicals on the leaves in this heat.

Thanks again.
Delores