Air - Humidity Measurement from Dry and Wet Bulb Temperature

Estimate air humidity by measuring dry bulb temperature and wet bulb temperature. Use lookup tables to determine relative humidity from temperature difference and dry bulb temperature.

Overview

Air humidity can be estimated by measuring:

Dry Bulb Temperature (Tdb) - measured with a simple thermometer
Wet Bulb Temperature (Twb) - measured with a thermometer wrapped in wet cloth with continuous air flow

The relative humidity is determined by the difference between these temperatures and the dry bulb temperature value.

Calculator

Inputs

Dry Bulb Temperature (°C)

Wet Bulb Temperature (°C)

Temperature Units

Results

Temperature Difference (Tdb - Twb)-- °

Estimated Relative Humidity-- %

Tdb - Twb (°C)	15°C	18°C	20°C	22°C	25°C	27°C	30°C	33°C
1	90	91	91	92	92	92	93	93
2	80	82	83	84	85	85	86	87
3	71	73	75	76	77	78	79	80
4	62	65	67	68	70	71	73	74
5	53	57	59	61	64	65	67	69
6	44	49	52	54	57	59	61	63
7	36	42	45	47	51	53	55	58
8	28	34	38	41	45	47	50	53
9	21	27	31	34	39	41	45	48
10	13	20	25	28	33	36	40	43

Tdb - Twb (°F)	60°F	64°F	68°F	72°F	76°F	80°F	84°F	88°F
1	94	95	95	95	96	96	96	96
2	90	90	90	91	91	92	92	92
3	84	85	85	86	87	88	88	89
4	78	80	81	82	83	84	84	85
5	73	75	76	78	79	80	80	81
6	68	70	72	73	75	76	77	78
7	63	66	67	69	71	72	73	74
8	58	61	63	65	67	68	70	71
9	54	57	59	61	63	65	66	68
10	49	52	55	57	59	61	63	65

Air - Humidity Measurement from Dry and Wet Bulb Temperature | MEPKit Engineering Tools | MEPKit