stop cold air around window cracks
It looks like the caulk there is old and cracked. Scrape it all out so you have a good surface to work with and use a premium acrylic caulk. DAP extreme stretch or 230 would be good choices if you dont want to work with silicone. If the gaps are larger than 1/4&quot; you should use window expanding foam or backer rod first to fill the gap before caulking. Then use a wet sponge and your finger or caulk tool to smooth out the bead