Try these links of different basemaps

Google Maps: https://mt1.google.com/vt/lyrs=r&x={x}&y={y}&z={z} Google Satellite: http://www.google.cn/maps/vt?lyrs=s@189&gl=cn&x={x}&y={y}&z={z} Google Satellite Hybrid: https://mt1.google.com/vt/lyrs=y&x={x}&y={y}&z={z} Google Terrain: https://mt1.google.com/vt/lyrs=t&x={x}&y={y}&z={z} Google Roads: https://mt1.google.com/vt/lyrs=h&x={x}&y={y}&z={z}

Dear Yi Zhou

These links might be helpful, have a look:

1. https://www.youtube.com/watch?v=sHOVw2zBbzI

2. https://gogeomatics.ca/qgis-worldclim-using-zonal-statistics-to-map-temperature-patterns/

3. https://www.youtube.com/watch?v=NVzcQOsxC_Y

Kind Regards

Qamar Ul Islam

The climate data is related to EPSG 4326, so just geographic coordinates. So it is up to you to select a proper map projection in QGIS: I am using OpenStreetMap as base map, it is matching quite well (see image for Lagos).

For the second part of your question, you will need the polygon feature of your provinces, they can be used to mask the "outside". For coloring, just use the symbology settings of QGIS

Here the image

Dear Yi Zhou , I highly recommend Dietrich Schroeder 's answer to you. However, to its orientations, I add that by using the polygon entity of your provinces or your country, they can be used to clip area of ​​interest.