Pest monitoring is crucial, especially during the early season, to understand the distribution and the proliferation of the target pest. Raw count data from pest monitoring/traps can be coupled with derived environmental variables such as growing degree-day ('GDD') to get useful insights about the pest phenology. This package pulls temperature data from the 'Daymet' application programming interface ('API', < https://daymet.ornl.gov>), or 'Open-Meteo' ('API', < https://open-meteo.com/>) or manual user-supplied CSV file from the California Irrigation Management Information System ('CIMIS', < https://cimis.water.ca.gov>), for a user-specified time period and calculates cumulative growing degree-days. Users provide intended date range, pest of concern, and the geographic coordinates of the trap location to track pest emergence and phenology throughout the growing season.