Table 1.

Treatment effect of an additional 6-h “Cone of Uncertainty" advisory

Birth outcomes	Effect of an additional advisory
	Rain > 2 in	1 in < Rain ≤ 2 in	Rain ≤ 1 in
Birth weight (g)	1.391	–4.815	–4.111***
	(1.099)	(3.023)	(1.449)
Mean dept. var.	3252.378	3281.767	3263.981
Gestation length (weeks)	0.00357	–0.0201	–0.0201
	(0.00304)	(0.0123)	(0.0131)
Mean dept. var.	38.526	38.544	38.543
Low birth weight (<2500 g)	–0.000629	0.00122	0.00206*
	(0.000403)	(0.00113)	(0.00105)
Mean dept. var.	0.090	0.084	0.087
Very low birth weight (<1500 g)	0.000131	0.000488	0.000846*
	(0.000218)	(0.000579)	(0.000484)
Mean dept. var.	0.016	0.015	0.015
Preterm (<37 weeks)	–0.00126**	0.00197	0.00114*
	(0.000496)	(0.00152)	(0.000666)
Mean dept. var.	0.103	0.102	0.102
Extreme preterm (<34 weeks)	0.000273	0.000514	0.00139*
	(0.000290)	(0.000898)	(0.000703)
Mean dept. var.	0.030	0.030	0.029
Observations	177,425	95,056	436,233

All models include month of birth and zip code fixed effects. The estimates for binary outcome variables are based on a linear probability model. Standard errors clustered at the county level are in parentheses. All t-tests are two sided (not reported). All econometric analyses were conducted using Stata/MP 16.1. Source data are provided as a Source Data file.

***P < 0.01, **P < 0.05, and *P < 0.1.