Summary1. Commercially available fluctuating-temperature chambers are large and costly. This poses a challenge to experimental ecologists endeavouring to recreate natural temperature cycles in the laboratory because the large number of commercial chambers required for replicated study designs is prohibitively expensive to purchase, requires a large amount of space and consumes a great deal of energy. 2. We developed and validated a design for economical, programmable fluctuating-temperature chambers based on a relatively small (23 L) commercially manufactured constant temperature chamber ($140US) modified with a customized, user-friendly microcontroller ($15US). 3. Over a 1-week trial, these chambers reliably reproduced a real-world fluctuating (13Á1-35Á5°C) body temperature regime of an individual frog, with a near-perfect 1 : 1 fit between target and actual temperatures (y = 1Á0036x + 0Á1366, R 2 = 0Á9977, 95% confidence interval for slope = 1Á0026, 1Á0046). Over 30-day trials, they also reliably produced a simpler daily fluctuating-temperature scheme (sine wave fluctuating between 10 and 25°C each 24 h) and a range of constant temperature regimes. 4. The design is inexpensive and simple to assemble in large numbers, enabling genuine replication of even highly complex, many treatment study designs. For example, it is possible to simultaneously examine in replicate chambers the responses of organisms to constant regimes, regimes that fluctuate following the means experienced by populations and regimes that exactly mimic fluctuations measured over any length of time for particular individuals that differ in behaviour or microhabitat use. These chambers thus vastly expand the pool of resources available for manipulative experiments in thermal biology and ecology.

To accurately characterize a species’ thermal niche and aid in predicting effects of climate change we must not only include information on thermal tolerances and physiological responses to changing temperatures, but also incorporate ecological effects and evolutionary processes that may shape a species’ niche. However, quickly and practically collecting data on key factors such as adaptation potential, behaviour, effects of species interactions, plasticity and thermal tolerances is logistically challenging. We have therefore created an adjustable temperature array (ATA) to assist with experimental ecology and evolution research. ATA’s are a row of independent temperature points controlled and set by the user and made from commercially available parts. This allows the user to create unique thermal landscapes relevant to their study organism(s) and question(s). Further, the option of using an enclosed cage allows the user to answer questions at the individual, population, or community level in the context of changing thermal environments. ATA’s are able to be user‐set to constant or dynamic temperature regimes and are designed for use on small animals (e.g. fruit flies, beetles, mosquitoes) or plants (e.g. germinating seeds). We have tested and confirmed the accuracy of the ATA to several thermal landscapes that would be useful for experimental ecology and evolution, including: (a) coarse resolution of a broad thermal niche ranging from 12° to 42°C in 2°C intervals (R2 = 0.998); (b) fine resolution of a narrow thermal niche ranging from 15° to 32°C in 1°C intervals (R2 = 0.997); (c) a pyramid‐shaped niche consisting of a gradient from 14° to 30°C in 2°C intervals (R2 = 0.997); and (d) a very narrow thermal niche with replicate thermal resources ranging from 26.5° to 34°C in 1.5°C intervals (R2 = 0.989). The equipment described here is an important tool for thermal niche studies and will aid in gathering information on effects of ecological and evolutionary processes to create a comprehensive picture of species responses to climate change.