Due to falling temperatures varroa treatments using oxalic acid are about the only option still available to ECWBA beekeepers. The temperature forecast for next week is high's in the 30's and lows in the 20's at night. These temperatures are too low for use of oxalic acid.
However this Saturday, Sunday and Monday temperatures will still be in the 40's. This is a last chance of application of oxalic acid. Sunday has rain predicted so your best bet is to treat on Saturday. This would be a good time to also reposition your entrance reducer to the smallest setting; one inch (1"). If you plan to use mouse guards this would be a good time to also install them.