10 miles to work -- I'm slow

On 5/18 I ran 1:49:23 with an avg 135 bpm. Today was 1:52:51 and 138 bpm. Weather on 5/18 was 46-51 deg. Today was 54-62 deg. Weather doesn't explain it I'm afraid. I'm slower. Gotta up them miles to make up for intensity.