@Martin i answered with specifics that question in threads like here comes the 2016, 2018, 2019 apple and pear threads. I usually put pears into two categories early and late ripening focusing on the disease resistant types only for most people. It looks like this E - Early L-Late as shown below. Late means fall , Early means summer. There are extremes of both. Korean Giant will the last pear your cold fingers likely touch for the year on that list. Clarks small yellow pear will be one of the first just like ayers.
Disease resistant pears
1.Clarks small yellow pear -10 -E
2.harrow sweet -8 -L
3.drippin honey -8-E
4.harrow delight -7-E
5. Korean giant -8-L
6. Ayers -7-E
7. Clara frijs-7-E
8. Seckle-6-E
9. Warren -7-E
10. Karls favorite-5-E
Here are additional specifics documented
Giving credit where credit is do sharing my research on pears would not be possible without @scottfsmith who built this great website. Many types of pears i grow would not be possible without the USDA aka ars grin at Corvalis but i have mentioned all that before many times Pear research is yielding results