Table 2.

Impact of weather factors on hourly trip counts in the San Francisco Bay area.

			Weekday				Weekend
Season	Variable	All trips	All weekday	Commute	Transit (commute)	Non-commute
All	Temperature (°C)	1.011 *	1.009 *	1.008 *	1.011 *	1.009 *	1.016 *
	Humidity (%)	0.993 *	0.994 *	0.994 *	0.99 *	0.994 *	0.989 *
	Wind speed (km/h)	1.007 *	1.004 *	1.009 *		1.003 *	1.022 *
	Precipitation (mm/h)	0.978 *		0.954			0.942 *
	Snow	–	–	–	–	–	–
	Thunder	1.868 *					1.707 *
	Cloud cover	1.224 *	1.214 *	1.225 *	1.565 *	1.200 *	1.157 *
	Heavy cloud cover		1.023			1.023
	Fog	1.473 *	1.317 *	1.611 *	2.651 *	1.165	1.770 *
Winter	Temperature (°C)	1.005 *	1.004 *			1.005 *	1.005 *
	Humidity (%)	0.993 *	0.995 *	0.997 *	0.994 *	0.994 *	0.988 *
	Wind speed (km/h)	1.007 *	1.005 *			1.008 *	1.015 *
	Precipitation (mm/h)	0.975 *	0.979	0.945
	Snow	–	–	–	–	–	–
	Thunder	1.842 *					1.540
	Cloud cover	1.191 *	1.245 *	1.240 *	1.774 *	1.242 *
	Heavy cloud cover	1.077 *					1.252 *
	Fog	1.505 *	1.357 *	1.565 *	2.757 *		1.818 *
Spring	Temperature (°C)	1.062 *	1.043 *	1.042 *	1.107 *	1.045 *	1.095 *
	Humidity (%)	0.998 *	0.997 *	0.996 *		0.997 *
	Wind speed (km/h)	1.014 *	1.009 *	1.013 *		1.008 *	1.026 *
	Precipitation (mm/h)		0.733
	Snow	–	–	–	–	–	–
	Thunder
	Cloud cover	1.283 *	1.265 *	1.301 *	1.411 *	1.240 *	1.197 *
	Heavy cloud cover	0.958					0.924
	Fog
Summer	Temperature (°C)	1.025 *	1.021	1.034			1.051 *
	Humidity (%)	0.995
	Wind speed (km/h)	1.016 *	1.011 *	1.018 *	1.031	1.010 *	1.027 *
	Precipitation (mm/h)					0.004
	Snow	–	–	–	–	–	–
	Thunder
	Cloud cover	1.151 *	1.104	1.208 *			1.156
	Heavy cloud cover
	Fog
Autumn	Temperature (°C)	1.033 *	1.032 *	1.051 *	1.062 *	1.026 *	1.037 *
	Humidity (%)	0.997 *					0.995 *
	Wind speed (km/h)	1.003 *		1.018 *			1.025 *
	Precipitation (mm/h)						0.920 *
	Snow	–	–	–	–	–	–
	Thunder
	Cloud cover	1.214 *	1.162 *	1.141 *	1.358	1.164 *	1.305 *
	Heavy cloud cover		1.064 *	1.106 *		1.055 *	0.928 *
	Fog	1.303 *					1.363

Note: Coefficients indicated with no asterisk are significant at α = 0.05 and coefficients indicated with an asterisk (*) are significant at α = 0.01. Variables corresponding to all insignificant coefficients were omitted during the model estimation process.