How long & at what interval do you want to take readings? This will help to decide on method of data gathering & choice of instrument. If it is for long hours at short intervals, being present all through becomes hectic using handheld thermometers. Define your data intervals & decide if handheld instrument or outdoor standalone instrument is appropriate. For outdoor standalone which are usually for continuous measurements, waterproof temperature sensor is always good for all conditions... dry or wet. Shielded temperature sensors are generally good for outdoor applications.

Dear Nino,

You can use thermistor based temperature sensors. For fast response you can choose small thermistors. They are very sensitive to the temperature variations.

There is also integrated circuit sensors that you can use them also: http://www.ti.com/sensors/temperature-sensors/overview.html

As for the data logging for sampling and acquire the temperature you can use dta loggers that accept the analog signal of the sensor. The storage capability of the loggers in number of samples must be sufficiently large to accommodate all the readings required to store.

You can consult an electronic engineer in your neighborhood.

Best wishes

First, you need to decide what animal or plant you are studying. Then you need to know its distribution if a plant or the range and types of environment you have to consider if it is an animal. For measurements in the atmosphere, thermistor observations using a data logger are best. However, make sure that the sensor is shielded from moisture and does not get buried in snow unless you need snow temperatures. For measurements in trees, place the sensors at different heights to determine the vertical variations in temperature. Remember that different aspects and vegetation covers have different thermal regimes. In soils, remember that snow pack depth can control the thermal regime in winter and the species of herbs determine the summer regime in tundra or grassland areas. Different lichens and mosses can greatly alter the moisture regime especially in cold climates

Thermometers are cheap but need calibration. You also have to read them frequently unless you are only interested in maximum and minimum temperatures throughout a chosen period of time. Thermistors work well and can operate on very low currents to conserve batteries. Data loggers come in several different kinds. For research purposes, ones which have multiple channels and produce downloadable data are best. They need suitable housing but plastic boxes work well with garbage bags if used inside cedar boxes. The cedar is poisonous to rodents, but they love teflon used as an insulator. Thermistors operate well in a range from -45 to +45 with good accuracy if they have been calibrated. Buy those with factory calibration rather than trying to calibrate them yourself. Button thermistors only store a specific amount of data before over-riding the data already in the memory. Plan your spacing of timing of observations to suit the memory capacity of the instrumentation. Programmable data loggers can measure a wide range of properties at the same time, not just temperature. They can save you many visits and are reuseable whereas some button loggers are throw away in type, even if they are cheap. Button thermistors usually measure the temperature at a specific point but you will need a multi channel machine to measure thermistor strings on a long term basis.

I hope thiis helps.

Stuart.